Nomenclatural and Taxonomic Review of Three Species
 and Two Varieties of Taxus (Taxaceae) in Asia

Table 1  Authors for species names of Taxus interpreted 
according to their morphological and /or geographical data.  

©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
PO Box 81145
Bakersfield, CA 93380-1145
April 2003; Dec. 2006, reformatted June 2010

Abstract

Taxus wallichiana Zuccarini, T. contorta Griffith, and T. chinensis (Pilger) Rehder are three species of the Himalayas and southwestern China that have been confused due to misunderstanding of their types and misapplication of their names. Their confusion has led to other superfluous species names—T. fuana Nan Li & R. R. Mill and T. yunnanensis W. C. Cheng & L. K. Fu—that in this study are distinguished as varieties, T. contorta var. mucronata Spjut, var. nov., and T. wallichiana var. yunnanensis (W. C. Cheng & L. K. Fu) C. T. Kuan.  Clarification is provided by designation of lectotypes.  The taxa are further distinguished by morphological characters in a key and in detailed descriptions.  This is followed by citations of specimens studied and a discussion of taxonomic relationships.

INTRODUCTION

Delimitation of species in Taxus has been a taxonomic problem due to neglect in applying standards (types) and rules (ICBN, Greuter et al. 2000) to the chosen names and to difficulties in determining species morphological characteristics. Taxus wallichiana Zuccarini is one example of three that I will discuss. It was described by Zuccarini (in Siebold & Zuccarini 1843) to clarify its relationship to the genus Torreya, which had been described only five years earlier based on the discovery of T. taxifolia Arnott (1838) in Florida. Siebold & Zuccarini (1843) realized that Taxus nucifera L. in Japan belonged to Torreya (T. nucifera (L.) Siebold & Zuccarini 1843, 1846), whereas collections by Wallich and others in the Himalayas identified as “Taxus nucifera?” (e.g., Wallich 6054A) were not that species. Siebold & Zuccarini (1843) also saw a similar problem with another species in Japan “T. cuspidata Sieb.& Zuccar.” validly published in footnote by specific reference to [a description (ICBN, Art. 32.4)] T. baccata in Thunberg (1784, Fl. Jap. 275, “foliis solitariis, linearibus, cuspidatis, approximatis”), which they also felt was distinct from T. baccata Linnaeus (1753, Sp. Pl. 1040,“foliis approximatis”) in Europe, T. globosa Schlechtendal (1838) in Mexico, and T. canadensis Marshall (1785) in northeastern temperate North America; undoubtedly, this disjunct geographic distribution justified each of them as distinct. Zuccarini did not cite specimens, but did provide a Latin description, an illustration, and a reference to another illustration and name (“Taxus nucifera?”) in Wallich (1826).

As Taxus was discovered in other regions, species differentiation became more of a problem. This included new species—T. brevifolia Nuttall (1849) from western North America, T. floridana Nutt. ex Chapman (1860) from Florida, and others from Asia erroneously placed in the genus Cephalotaxus—C. sumatrana Miquel (1859) from Sumatra and C. celebica Warburg (1900) from Celebes (Pilger 1903). Pilger (1903), in a monograph of Taxus, decided there was only one species, T. baccata.

Pilger (1903), however, recognized six former species as subspecies. In addition to ssp. baccata, these included: 1—wallichiana, 2— cuspidata, 3—brevifolia, 4—canadensis, 5— floridana, and 6—globosa; the latter two subspecies were later considered to hardly differ from ssp. canadensis (Pilger 1916, 1926). He also described two new varieties (Pilger 1903; under ssp. cuspidata), var. latifolia and var. chinensis, and recognized 21 forms of baccata (Pilger 1903, 1916). He applied morphological characters that seem to best fit a phytogeographic separation of the taxa; for example, ssp. wallichiana was characterized by lax branching and persistent bud-scales, and by leaves more or less falcate, rigid, narrowly linear, 2.5–3.0 cm long, notably arcuate at base, and acuminate or acute; 12 representative specimens were then cited from eastern India to Sumatra. He also cited synonyms with reference to the source publications where further citations of specimens may be found, including presumed types in cases where only one specimen is cited, but types were not indicated as this generally was not the practice then.

Although it might be argued that the lack of any significant variation in cone structures of Taxus hardly justifies recognition of more than one species (Pilger 1903), other taxonomists still maintained geographically distinct populations as species (Cheng & Fu 1978; Florin 1948a; Hu 1964; Rehder 1919, 1936, 1940; Wilson 1916), sometimes describing new species without a clear understanding of types or nomenclatural rules.

This has led to much confusion to interpreting species of Taxus, particularly T. chinensis (Pilg.) Rehder (1919) and T. wallichiana. For example, Rehder (1936), upon discovering that Tsuga mairei Lemée & H. Léveillé (Léveillé 1914) belonged to Taxus, treated it as a synonym of T. chinensis; the ICBN (Art. 11.4) requires that the earlier epithet, mairei, be adopted. S. Y. Hu (in Liu 1960) made the combination, but excluded Cephalotaxus celebica and C. sumatrana because their types were not available or known to her. Then Cheng & Fu (1978) established T. chinensis var. mairei, an illegitimate combination that had been earlier introduced invalidly (Cheng et al. 1975; ICBN Art. 33.2). This was transferred—T. wallichiana var. mairei (Lemée & H. Lév.) L. K. Fu & Nan Li (in Li & Fu 1997)—but this too is illegitimate; the authors failed to account for types of T. baccata var. sinensis A. Henry, C. celebica Warburg, and that of Cephalotaxus sumatrana Miq—earlier valid names that must be considered (ICBN Art. 11.5), especially since the epithet mairei does not have legitimacy below the rank of species (see also Art. 45.3). However, the circumscription of this taxon was emended by arbitrarily excluding names of Taxus outside of the Flora of China (Fu et al. 1999).

Florin (1948a), who on one hand recognized Henry 7155 as the type for his new combination, T. wallichiana var. chinensis, did not clearly identify the type for T. wallichiana when he made that combination.  Additionally, he distinguished a new species, T. speciosa, for which he cited an earlier legitimate name whose epithet should have been adopted (Cephalotaxus celebica Warb.) as later done by Li (1963), whereas de Laubenfels (1978, 1988) applied an earlier name, Cephalotaxus sumatrana Miq. (Pilger 1903, 1916), but also excluded T. wallichiana for reasons that are not clear. W-c. Cheng & Fu (1978), along with C-y. Cheng (1975), described T. yunnanensis because they assumed from literary accounts that T. wallichiana occurred mostly in the western Himalayas (Li & Fu 1997), whereas Hu (1964) had correctly recognized it. Li & Fu (1997), attempting to rectify the error, decided that T. yunnanensis should be placed in synonymy, and in so doing published another superfluous name—T. fuana Nan Li & R. R. Mill for T. contorta Griffith—the name for the common yew in the western Himalayas.

Besides nomenclatural confusion, herbarium specimens themselves are often confusing, and no doubt this has contributed more confusion. Labels are sometimes attached to the wrong specimens (e.g., Wallich 6054A), or label data are not always consistent for the same collection found in different herbaria (e.g., Griffith 5002), or the same number has been applied to many specimens from a wide geographic area (e.g., George Forrest in Yunnan; Cox 1945), or different letters may be appended to differentiate collectors or geographical variants (e.g., Wallich 6054/A, B, C, D, & E), or mixed specimens are often mounted on the same sheet.

Examples for all of these have been seen on Wallich specimens of T. wallichiana regarded as original material, which might be equivalent to syntypes and isosyntypes except for the fact that no specimens were cited by Zuccarini in Siebold & Zuccarini (1843). These specimens may be labeled 6054A, or 6054B, or without number; one from München has a label indicating it was collected in Japan, but it could have been collected only in the Himalayas based on its morphology. Parlatore (1868), Pilger (1903), and Nasir & Ali (1987) interpreted both Wallich 6054A and 6054B to belong to T. wallichiana, while others recognized only 6054A (Hara et al. 1978) as that species. Wallich 6054 also included further designations of C, D, and E for which I have not seen specimens; these probably belong to other genera. Additionally, Wallich 6055 has reportedly been collected in northwestern Himalaya by [Dr. George] Govan & Webb, and identified Taxus baccata L.? (Anonymous 1913); I have not seen this either. Most specimens of Wallich 6054A (from Nepal) belong to T. wallichiana, while most Wallich 6054B (from Kumaon) are T. contorta.

This paper clarifies the taxonomy of three confusing species of Taxus—T. wallichiana Zucc., T. contorta Griff., and T. chinensis (Pilg.) Rehder—that occur from the Himalayas to southwestern China.  Their (lecto)types are designated, morphological features are described, and taxonomic relationships are discussed.  Clarification is needed because of interest in the anticancer compound taxol (Kingston et al. 1990; Kingston 1996; Wani et al, 1971) and related taxoids in Taxus (Appendino 1995; Croom 1995) that are being reported under species names without any indication as to how they are distinguished.

METHODS

Stafleu & Cowan (1976–1988) were consulted for location of types, other specimens of historical relevance to this study, and references. I studied more than 1000 herbarium specimens (A, BH, BM, BOLO, E, GH, K, M, NA, NY, P, PE, PH, S, U, US; Holmgren et al. 1990) of Taxus from throughout the natural range of the genus to assess morphological variation in characters that involve branches, bud-scales, leaves, and cones. Each specimen was photographed using 35 mm color film in a Nikon camera with 35 mm and 60 mm lenses. From each specimen one mature leaf was soaked in water (8-16 hrs) and then transversely and longitudinally sectioned in the mid regions, using a single-edge razor blade and dissecting needle as a guide; the longitudinal sections consisted of the ventral (abaxial) epidermal layer (with parenchyma scraped-off), usually from 0.5–2.0 mm, occasionally the entire abaxial surface of the leaf. These sections were examined under magnifications of 100×, 250×, and 400× (using a Nikon binocular microscope) for cell shape, number of stomata rows, number of cells marginal to stomata bands, and presence, position, and distribution of papillae. The results were sketched and described on 3 × 5 inch packets. A temporary slide of the sections and photographs of the herbarium specimen were retained for each packet. Additionally, many leaves from a single plant of selected species were also studied. This included, top, middle, and lower branches of T. brevifolia from trees in California and Oregon, young and old shoots of Taxus spp. from Taiwan and cultivation, and of cultivars related to T. cuspidata.

This study initially attempted to identify morphological features that would satisfy the geographical taxa concept mentioned earlier in the introduction (Spjut 1992, 1993; Spjut in Hils 1993); however, this concept could not be justified for specimens from Eurasia.  Herbarium specimens were then classified according to pattern recognition of shared morphological features.  These involved characters of branching pattern, persistence of bud-scales, texture of bud-scales, length of bud-scales, color of branchlets, leaf arrangement, leaf shape, leaf thickness, leaf color, leaf curvature lengthwise, leaf curvature across adaxial surface, midrib on adaxial surface, leaf margins, shape of cones in bud, at maturity, and others.  In May 1994 a list of characters and their character states were created in DELTA (DEscriptive Language TAxonomy) format as done in other studies (see Spjut 1996).  This list included 85 morphological characters, 44 of which involved leaf anatomy. Specimens were reviewed for scoring character states in each of 15 species items.  Variations in certain character features that appeared significant were treated as item variants; 23 were identified.  Species descriptions were then generated using DELTA software and were subsequently modified by word processing software.  The DELTA format was maintained until May1996 when it was decided that changes in keys and descriptions, which had been done frequently, were much easier for this author  to make looking at real language descriptions rather than in numerical codes.

Author names of plants for species of Taxus are spelled out in full when first mentioned, in references to publications, and in literature cited; elsewhere, they—along with authors for species names in other genera—are abbreviated according to Brummitt & Powell (1992).  Literature for nomenclatural citations is abbreviated according to Stafleu & Cowan (1976–1988), except journals.  Reference to color is based on comparison of specimens or leaves with a commercially available color chart  (Berol Prismacolcor), which shows 120 different colors on a single page, each with a descriptive name.

A major loan from Harvard (A, GH), and smaller loans from Kew (K), Bailey Hortorium (BH), München (M), and Utrecht (U) had to be returned though the curator at the U. S. National Arboretum (July 1996) before this study was completed because the USDA Agricultural Research Service could no longer support this research. Consequently, these specimens were annotated (in adnot.); this included designation of types and notations for names not yet published (“Spjut ined.”). However, this study continued in World Botanical Associates with further reviews of specimens at the British Museum of Natural History (BM), Kew (K), U.S. National Arboretum (NA), Paris Museum of Natural History (P), Academy of Natural Sciences of Philadelphia (PH), and U.S. National Herbarium (US), while other loans were obtained from the Royal Botanic Garden at Edinburgh (E) and Swedish Museum of Natural History in Stockholm (S). Additionally, I have studied more than 400 fresh specimens from England, France, Sweden, China (Sichuan, Hubei, Gansu, “northeast”), Korea, Japan, Philippines, Taiwan (Hualien, 11 locations; “Tong-shi,” “Dong-shi”) Mexico, Canada (BC), and United States (CA, OR, WA, ID, MT, OH, WI, NH, ME, FL), and also photographed and reviewed living yew collections at Kew Gardens in England, National Arboretum in Washington, D.C., and Secrest Arboretum in Wooster, Ohio.

Needles from a number of herbarium specimens were subjected to DNA extraction, but there was little extractable DNA (Krupkin, pers. comm.). Employing RFLP; Vance & Krupkin (1993) have distinguished chloroplast DNA among T. baccata, T. brevifolia, T. canadensis, T. cuspidata, and T. floridana.

Species of Taxus are differentiated by vegetative features, usually two or more character attributes that appear to be correlated; however, taxonomic weighting is given to single character attributes where it was necessary to maintain taxonomic clarity in related species.  Analysis is largely subjective, but see phytogeographical data for number of leaf stomata rows and number of marginal cells that border stomata bands (defined by the absence of papillae), and for leaf divergence.

TAXONOMIC PHILOSOPHY

Taxus cones show only minor differences; thus, evidence for reproductive isolating mechanisms is difficult to evaluate.  This is further complicated by the dioecious habit for most species except T. canadensis. 

One of the yew’s reproductive strategies is to survive by vegetative reproduction.  Yew trunks have been reported be several thousand years old (Loudon 1844; Silber and deWolf 1970; Voliotis 1986), and when they fall they do not necessarily die; they can live on by regenerating from branches that root (layering), or by stump sprouts (Loudon 1844)—until, perhaps, a climate change forces them out, or to adapt.

Despite the lack of morphological or chemical reproductive isolating mechanisms in Taxus, species status appears warranted for populations exhibiting morphological differences in vegetative features that appear to have evolved over millions of years (Spjut 2007a).

Substantial polymorphism exists within species populations of Taxus as reported for T. brevifolia (Doede et al. 1993), and three genetically different groups have been recognized in British Columbia (El-Kassaby and Yanchuk 1994); however, morphological data for genetically distinct populations or individuals was not studied.  Nevertheless, morphological differences among related North American species of Taxus are relatively minor compared to their relatives in Asia (Spjut 1993, 1998a; Spjut in Hils 1993). This is not surprising in view of one of the world’s richest gymnosperm areas lies in Sichuan, China, where 88 species in 27 genera occur, among which there are 14 endemic species represented by “living fossils” in Cathaya, Gingko, and Metasequoia, and there are other notable relict species in Abies, Amentotaxus, Cephalotaxus, Cryptomeria, Cunninghamia, Cycas, Keteleeria, Pinus, Picea, Podocarpus, Torreya, and Tsuga (Anonymous 1994); California, by comparison, has 60 species in 14 genera of which 7 species are endemic (Hickman 1993). Many relicts occur in southwestern China because the climate remained relatively mild during the Pleistocene, whereas in Europe and North America the glacial climate caused greater devastation to their floras (Anonymous 1994).

The disjunct distribution of extant Taxus in North America (Ferguson 1978) might be correlated with paleobotanical evidence since the Oligocene (27–38 mya)—as summarized in numerous historical accounts (e.g., Axelrod 1975, 1976, 1986; Frederiksen 1994, 1995; Graham 1972, 1973, 1993, 1999; Srivastava 1994; Wolfe 1975), but evolution of Taxus may date back to the Triassic (Florin 1958, 1963; Harris 1976; Meyen 1984; Miller 1976, 1977). A summary of the fossil record by Gaussen (1979) listed 11 extinct species of Taxus from Eurasian Tertiary deposits, three from Mesozoic Eurasian deposits, and various indeterminate species, including three records from North American mid Tertiary deposits.  However, identifications of Taxus fossils are not always reliable (Harris 1976). Taxus jurassica Florin, for example is clearly not Taxus; it has opposite leaves, not spirally arranged leaves (Harris 1976). Several other related species from Jurassic and Cretaceous deposits have narrow stomata bands similar to T. jurassica (Florin 1958; Kvaček 1986), and in my opinion are not Taxus. Kvaček (1986) mentioned several other species, T. inopinata Givulsec, and T. grandis Krausel and described two others (Taxus sp. 1, Taxus sp. 2) from Lower Miocene and Upper Plicoene deposits that I cannot differentiate from modern T. canadensis, which I also recognize to occur naturally in Europe and W. Asia (Spjut 2000).  The genus Taxus is defined by its phyllotaxy of spirally inserted leaves with hypostomatic papillose bands (Dilcher 1969; Florin 1931; Kvaček 1986).

From my extensive study of leaf characters, I have seen many examples of continuous variation that would be best explained by gradual evolution, while I have also seen many examples of different character combinations involving habit, phyllotaxy, seed shape, and leaf anatomical features that indicate frequent hybridization (Spjut submitted).  In flowering plants, the evolution of vicarious species is often attributed to cyclic climatic changes as glaciers advanced and retreated during the past 2.5 million years (e.g., Prance 1982); in Taxus such changes may have done more to promote hybridization between formerly distinct species. Evidence for such hybrids has been reported in other conifers, e.g., Picea rubens Sarg. and P. mariana (Mill.) Britton, Sterns & Poggenb. (Bobola et al. 1996), Picea glauca (Moench) Voss, and P. engelmannii Parry ex Engelm. (Wilkinson et al. 1971), and species of Pinus (Axelrod 1986).

Recently, Manchester (1994) described T. masonii from seed in Middle Eocene deposits of Oregon. It was distinguished from seed of extant species by the lenticular shape, which might be compared to that of T. chinensis and English yew. Another extinct species, T. engelhardtii Kvaček (1986), from a late Oligocene deposit in Bohemia (Czech Republic), is similar to extant T. mairei in phyllotaxy and to T. chinensis in leaf anatomy; however, rare extant specimens of Taxus from China also show these combined features. The taxonomic differences in species of Taxus described below are believed to have evolved before the Miocene (5+ mya) based upon comparative morphological data for extant plants on North America, Europe, and Asia (Spjut 1993, 1998a, 2000a, b, c), and the occurrence of T. canadensis in North America, Europe, and W Asia (Spjut 2000a, b, c).

KEY

The results are species descriptions as defined by a key based on data from dried specimens; the distinction in color may not be the same for live material (Spjut 2000c, submitted).  The key presented here pertains only to the three species in this paper. All key features should be considered equally except where weighted (bold type).  Other related species are excluded from the key, but their relationships are discussed. Phyllotaxy is spiral but leaves often twist along their petioles and blades to spread ± in two ranks.  Distribution data are from herbarium specimens and the locations are correlated with references to vegetation types that cited Taxus. The vegetation types mentioned are not standardized. Nomenclature and references for the three species and their varieties are discussed according to priority of publication: (1) T. wallichiana, (2) T. contorta, and (3) T. chinensis.

 

1. Dried leaves with loose, dark reddish parenchyma cells, resembling
broken egg shells, usually falling out when leaves are sectioned;
stomata in (5-) 7–8 (-11) rows/band; leaf epidermal cells often elliptical
in transverse sections, especially in NW Himalayan plants; seed
subcylindrical to subglobose (Fig. 2)…………..……................................…… T. contorta—2

2. Leaves 12 or more times longer than wide, virgate, spreading
by petiole, the petiole curved (Fig. 1); stomata 5–8 (9–11)
rows/band; Afghanistan, Pakistan, India, W Nepal….................................. T. contorta var. contorta

Fig. 1–2: Taxus contorta var. contorta, Fig. 1 (left): Shows characteristic long
straight leaves,  Stainton et al. 5616, from Nepal (BM). Fig. 2 (right): example of
subcylindrical seed shape, Pingelly s.n., from India (K).

2. Leaves 5–10 times longer than wide, sharply (bent) reflexed at
petiole (Fig. 3); stomata 9–11 rows/band; Nepal, SW Tibet, Bhutan…......... T. contorta var. mucronata

Fig. 3. Taxus contorta var. mucronata showing reflexed
leaves, Ludlow et al. 16035, from Bhutan (GH).

Fig. 4: Taxus chinensis, with pointed angled seeds,
Sino-Amercan Exped. 1854, from Guizhou, China (GH).  

1. Dried leaves with adhesive reddish to greenish parenchyma cells; stomata 11–21 rows/band; leaf epidermal cells angular or elliptical in x-section; seed conical, gradually tapering to apex from mid region (Fig. 4)…. 3

3. Older branchlets lacking yellowish tint, often abruptly
darkening from yellowish green to dark maroon in
2nd yr, or reddish orange in specimens from NE India;
bud-scales usually persistent at base of branchlets;
tooth-like to cuspidate (Fig. 5); leaves mostly linear
arcuate near base; leaf epidermal cells mostly
angular in x-section (T. wallichiana)……....….. 4
Fig. 5.  Taxus wallichiana Hooker & Thomson 77 ex Herb. Bunge, from Khasia, India (P).

4. Leaves nearly lanceolate in plants from Sichuan and Yunnan (Fig. 6),
or linear in plants from NE India to Tibet; in x-section long and narrowly revolute
towards margin; leaf epidermal cells in x-section
often enlarged along abaxial marginal zone, 35–50 µm wide, papillae
mostly opposite on marginal and midrib cells; NE India, Myanmar,
SE Tibet, Yunnan.......... ……………………..T. wallichiana var. yunnanensis

Fig. 6. Taxus wallichiana var. yunnanensis, Wang 67412 from Yunnan, China (A).

Fig. 7. Taxus wallichiana var. wallichiana, Griffith 5002 from “East Himalaya” (P).

4. Leaves linear (Fig. 7, 9–10); not long tapering to the margin in x-section;
abaxial surface with epidermal cells in x-section not enlarged, generally
shorter than those on adaxial surface, 15–25 µm wide,
decreasing in length near margins; papillae mostly alternate on midrib and
marginal cells, or along cell walls (Fig. 6); NE India, Nepal, Bhutan,
Myanmar, Sichuan, Yunnan………………..…...…T. wallichiana var. wallichiana

 

3. Branchlets pale greenish with a
yellowish tint, gradually darkening
from young to older branchlets; bud-
scales vestigial, or not at all
persistent (Fig. 8); leaves narrowly
elliptic to oblong; leaf epidermal cells
usually elliptical in x-section, rarely
angular; Vietnam, China...................... T. chinensis

Fig. 8. Taxus chinensis. Wilson 624, from Mount Emei, Sichuan, China (A).

NOMENCLATURE, DESCRIPTION, AND DISCUSSION

1. Taxus wallichiana Zuccarini, in Siebold & Zuccarini, Abh. math.-phys Cl. k. Bayer. Akad. Wiss. (München) 1 (3): 803, Tab. 5 (Fig. 9). 1843. Taxus baccata subsp. wallichiana (Zucc.) Pilger in Engler, Pflanzenreich IV (5): 112. 1903. Taxus baccata var. wallichiana C. K. Schneider ex Silva Tarouca, Freiland-Nadelgehölz. 276. 1913. No specimens cited by Zuccarini, original material at M: specimens from NEPAL, INDIA. Lectotype (designated by Spjut in adnot. 23 Mar 1995, in J. Bot. Res. Inst. Texas 1: 230. 2007): specimen with male cones, “Herb. Zuccarini”—India: eastern, communicavit Wallich, year 1835—Wallich s.n. (Fig. 10, M!). Other related material: Wallich 6054A, p.p.,“Kumaon,” with Schultes label, in adnot. Torreya nucifera, Taxus nucifera, and Taxus wallichiana, one large branch with mature male cones (M!). Duplicates of Wallich 6054 (see below): GH! K! NY! P! PH! S! 

1a. Var. wallichiana. Shrub or tree to 20 m or more; branchlets yellowish green, or reddish orange, becoming gradually darker in age, or abruptly dark purplish (maroon) in 2nd yr; bud-scales persistent at base of 1–2 yr branchlets, these pale yellowish to brownish red (maroon), usually numbering 5–10, overlapping in 3–4 ranks, the lower scales loosely adnate, ovate, ca. 0.5 mm long, upper scales spreading, concave and incurved towards apex (cuspidate), to 1 mm long. Leaves ± evenly spreading but not evenly distributed, linear, acuminate, straight to commonly falcate, 1.5–3.5 cm long, 1.5–2.5 mm wide, usually ca. 350 µm thick, thinner in plants of NE India bordering Myanmar and Tibet, glossy (resinous) dark green above, paler below, convex on upper surface to a rounded midrib, less concave below to a flush to slightly rounded midrib, becoming revolute near margins (80–90º), especially in upper third of dried leaves; upper (adaxial) epidermal cells angular in x-sect., rectangular, quadrangular, or taller than wide, commonly ca. 25 µm diam., or 20–30 µm tall and 20–40 µm wide; abaxial epidermis papillose except for  (2-) 4 (-6) cells across from margins, or 4–6 (-8) cells wide in plants from Mt. Emei (Sichuan), the epidermal cells usually not inflated, short rectangular, 1.5–3 times (×) longer than wide (l/w),  gradually becoming quadrate or short trapezoidal but not particularly narrower towards margin, occasionally long rectangular near margins in plants from Nepal (4–8× l/w) but then not tall, usually 8–12 µm tall, (10-) 15–25 µm wide, similar in shape and length on midrib, or often narrower and longer on midrib, 3–10× l/w; papillae usually distinct, often aggregate, positioned more marginally than medially in 2–3 alternate rows, or medial in some specimens but then cells not inflated; stomata usually 11–18 (-21) rows in yellowish green to reddish orange bands (dried leaves), the stomata rows generally decreasing in number from east to west, palisade parenchyma 1 row, generally 50–70 µm long; spongy parenchyma cells ellipsoidal to bone-like, forming a periclinal net, not falling apart when sectioned. Male cones maturing on 1st and 2nd yr branchlets, ca. 1.5 wide and 4 mm long in bud, to 2 mm wide and 6 mm long at maturity. Female cones maturing on 1st or 2nd yr or older branchlets; seed conical in upper third, 6 mm long, 4 mm diam., slightly thickened at base, recessed at attachment point, with red or yellow aril.

Wallich yew. Distribution: E Himalayas to SW China; montane coniferous forests with Picea, Abies, Tsuga, or broadleaved evergreen forests of Lithocarpus, or Quercus, (1500-) 2300–3200 m; C & E Nepal, Bhutan, NE India (Assam, Manipur, Khasia Hills, West Bengal), Myanmar, China (SE Tibet, Sichuan, Yunnan). In Nepal evidently occurring abundantly with Abies spectabilis (D. Don) Spach on limestone (Stainton 1972), and in Bhutan apparently scattered from Ha to Mongar districts (Grierson and Long 1983).

Representative Specimens—Nepal: Arun Valley, N of Kutiar, 9000 ft., Stainton et al. 1398 (BM); Eastern Nepal, Duon Kosi, Chaunrikarua, 27º40'N, 86º40'E, 9500 ft, Stainton et al. 6601 (BM); Stainton et al. 4496 (BM); Solukhumbu Dist., Dudh Kosi River, Lamujo to Chumava, 2450 m, Hideo Tabata et al. 10585 (A, BM); Thulo Kobar to Ran Thanti, 83º45’ E, 28º24’N, 2600 m, Ohba et al. 8310264 (BM). Bhutan: Tunle La, near Kinga Rapden, 27º27’N, 90º37’E, 11,000 ft, Ludlow et al. 18672 (BM, GH); Thimphu Dist., summit of Dochong La, 27º29’ 89º45, Tsuga/Rhododendron forest, 3110 m, Grierson & Long 4417 (A); 7500 ft, Cooper & Bulley 2600 (BM); above Motithang directly W of Thimphu, Bartholomew & Boufford 3917 (A); illegible, 9000-10,000 ft, Griffith 2006 (BM, K, p.p., with T. sumatrana). India—West Bengal: Singalila Range, along trail from Rimbick to Sandakphu, 8400 ft, very large tree with circumference near base of 11’6", Voss et al. 148 (NA). Assam: without additional locality data, Griffith 2706 (BM). Khasia [Meghalaya]: 4500 ft, Vale of rocks, C. B. Clarke 436743 (BM); Khasia, 5000–6000 ft, J. D. Hooker 77, 87 (GH, p.p., lower left of 3 specimens on one sheet; P; PH).  East Himalaya, without locality, Griffith 5002 (P: 2 sheets, one distributed by K, the other ex Herb. Bunge). Manipur: Seriphari, 10,000 ft, Jan. 1882, G. Watt 5955 (GH, P), 6208 (P), 6493 (P). Sirhoi: 8000 ft, small tree, scattered in forest, not common, only conifer above 7000 ft, Kingdon Ward 17271 (A, BM). India (without specific locality data), K. Biswas 439 (A, US). Myanmar (Burma): Northern: Adung Valley, 27–28º30'N, 97–98º30'E, 7000-8000 ft, shrub, of dry forest, Kingdon Ward 9375 (A); Adung Valley, 6000 ft, shrub, scattered through the thickets along river, Kingdon Ward 9214 (A, BM). China—SE Tibet: Cha Yu, 2370 m, tree ca. 15 yrs in age, occurring with Pinus sp., ChaYu Forestry Bureau Staff Expert CYW007 (ChaYu Forestry Bureau). Sichuan: Mt. Emei [Shan], 2300 m, Yu-shih Lin 1196 (A, US); 2400 m, T.T. Yu 482 (A), 492 (A); W. P. Fang 3945 (A); W.K. Hu 8166 (A); T.C. Lee 4465 (A); Pan-lan-shan W of Kuan Hsien, 5000–6000 ft, Wilson 4053 (A, BM, US). Yunnan: Salween, Kiukiang Divide, Shawlongwang, 2600 m, among mixed forest in valley, tree 40–60 ft, bark purplish brown, thinly scaly, leaves dark green above, yellowish beneath, seed brownish green, half covered by the coral red fleshy aril, rare, Nov 1938, T.T. Yu 21036. Cultivated—India: Dehra Dun, Bot. Gard. Darjeeling, Raijada 18919 (A). Specimen data questionable: Uttar Pradesh (Kumaon): Blinkworth s.n., in adnot. T. virgata (BM), probably not collected by Blinkworth and probably not collected in Kumaon.

Duplicates of Original Material (Isosyntypes) by institution: GH: label with handwriting similar to Wallich, “Taxus nucifera Wall.” “Napalia.” s.n. K: Four sheets. (1) with two specimens, the larger specimen has a pasted label below it with handwriting “6054a” and no indication of locality data, the smaller one is a single branch with mature seed, correctly annotated T. wallichiana by S. G. Harrison, but it is not 6054A, or not a type since it is not from a male plant; (2) two specimens, one large specimen with an imprinted stamp nearby—Herb. Hookerianum, with handwriting similar to Wallich, 6054/A, Nepal, accompanied by a smaller specimen in left corner, with a large label below, Watt 6493 from Munipur, det. T. wallichiana by Spjut; (3) has four specimens, but only the lower left specimen is a type (T. wallichiana), below it are several labels, one printed—ex Herb. George Gordon, presented by J. D. Hooker, 1878, the other bears handwritten annotation—"Taxus wallichiana," two largest specimens with letters a and b written nearby on left and right, respectively, and with Herb. Benthamum imprinted in center, belong to T. contorta; uppermost annotated T. virgata, det. by Spjut to be a young shoot of T. baccata. NY: 2 sheets, 6054A, NY accession numbers 30328 and 30329 (det. via photocopy). P: “Napalia,” 6054 with “A” inserted, annotated Taxus nucifera Kaempf.? on label ex. Herb. Richard, and additional label ex. Herb. E. Drake. PH: “6054A Wallich.”

 

Lectotype (M): India, eastern, with annotation label by R. Spjut, 23 Mar 1995.  Specimen on right shows closer view of male cones and persistent scales at base of branchlets.

 

 

 

 

 

 

 

 

 

 

 

 

 

India-Assam: Griffth 2(7)606 (BM).  Right photo shows close-up of male cones and persistent scales at base of branchlets, which are rather pale yellowish-green to pale orange.  Sketch on packet indicates abaxial leaf margin has 4 rows of smooth cells followed by 7 rows of papillose cells, 15 stomata rows and a midrib 15 cells wide; papillae are marginal (alternate) on both midrib and marginal cells.

 

 

 

 

 

 

India-Khasia [Meghalaya]
 J. D. Hooker 77 (GH), p.p. lower left of 3 specimens, T. wallichiana, shown in closer view on right; right specimen in left photo, T. contorta; upper specimen in left photo, T. sumatrana.  Note loose pale scales (but similar in color to branchlets) at base of branchlets in right photo.  Specimens from China that have similar scales but shorter (oblong) leaves are referred  to T. scutata (see examples of T. scutata in Chinensis Subgroup). Lower photo, specimen at PH.  Leaves from duplicates at P and at US were found to be identical in having 4 smooth marginal cells followed by 7 rows of papillose cells, 16 rows of stomata and 15 midrib cells with marginal papillae.

 

 

 

India-Manipur: Watt 5955 (P). A leaf from this and from an identical specimen in A were found to have 17 stomata rows per band.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bhutan: Thimphu District, Grierson & Long 4417 (A). Photos and packet attached to specimen, all returned to A thru NA in July 1996.  Upper photo shows stomata band, lower photo shows midrib with marginal papillae (along cell walls), also indicated in illustration on packet.

 

 

 

 

 

Bhutan: W of Thimphu, Bartholomew & Boufford 3917 (A).

 

 

 

 

 

 

Sichuan: Mt. Emei, W. K. Hu 8166 (A).  Photo on left shows authors sketch (returned with loan). Abaxial surface of leaf indicated to have 4(-6) rows of marginal cells followed by 9 rows of papillose cells and 18 rows of stomata.  Leaf x-section shows reddish rectangular epidermal cells. Photo on right shows sharp contrast between young pale orange and older reddish purple branchlets with persistent scales at base of branchlets.

 

 

Sichuan: Mt. Emei, 2300 m, Yu-shih Lin 1196 (A).  Illustration and photo attached to specimen and further enlarged by separate scan. Photo shows abaxial surface of leaf, stomata bands in part and midrib region magnified 250x.  Here stomata can be seen on the narrow midrib.  Papillae mostly alternate in position along epidermal cells (marginal papillae).

 

Nepal: 10,000 ft., Stainton et al. 8296 (BM).  Sketch of x-section of leaf in mid region shows distinct quadrangular epidermal cells; lower part of sketch indicates abaxial leaf margin has 3 rows of smooth cells followed by 8 rows of papillose cells, and a stomata band with 11 rows of stomata; papillae are shown to be alternate along narrow midrib cells and on wider marginal cells.  Leaves of this plant are shaped similarly to T. contorta, while the scales at the base of branchlets are more like T. wallichiana.  Number of stomata rows and geographical occurrence are borderline between the two species.  Leaf shape in x-section, absence of reddish parenchyma cells in the mesophyll region, and angled pointed seed are features that agree more with T. wallichiana.  

Nepal: Solukhumbu Dist., Dudh Kosi River, Lamujo to Chumava, 2450 m, Hideo Tabata et al. 10585 (A).  Sketch of leaf sections shows distinct quadrangular in leaf x-section, and abaxial margin to have 4 rows of smooth cells followed by 6 rows of papillose cells and a stomata band with 12 stomata rows. A leaf from a specimens at BM was found to have 11 stomata rows, and the epidermal cells were papillose to near the margin.

 

 

 

 

 

 

 

 

 

Myanmar (Burma). Northern: Adung Valley, 27–28º30'N, 97–98º30'E, 7000-8000 ft, shrub, of dry forest, Kingdon Ward 9375 (A).  Packet shows sketch of leaf sections.  A x-section indicates epidermal cells are quadrangular, 25 µm wide & tall; the abaxial leaf margin is indicated to lack papillae across 4 cells, followed by 10 rows of papillose cells, and a stomata band has 19 rows of stomata; papillae are noted to be marginal. 

 

 

 

 

 

 

 

 

 

Yunnan: Salween, Kiukiang Divide, Shawlongwang, 2600 m, T.T. Yu 21036 (A).  Image on right reproduced from Kwei, Y-l. and S-y. Hu. 1974. Epidermal feature of leaves of Taxus in relation to taxonomy]. Acta Phytotax. Sin. 12(3): 329-334, plate 67, Fig. 1, referred to as T. wallichiana var. chinensis. Abaxial leaf surface x65, showing midrib and stomata bands on each side.  Leaf shape in cross-section compares with var. wallichiana, but general leaf shape and arrangement along with position of papillae agree more with var. yunnanensis.

 

 

 

 

 

 

 

 

 

The lectotype was selected from several Wallich specimens among Zuccarini collections at München that best matched the illustration (Siebold & Zuccarini 1843, Tab. 5); however, Zuccarini (Siebold & Zuccarini 1843) did not cite specimens. Thus, the Wallich specimens of T. wallichiana studied by Zuccarini might appear to be syntypes, while those in other herbaria not seen by Zuccarini could be considered isosyntypes.  This would be the case according to the International Code of Zoological Nomenclature; however, the ICBN is not clear on this issue.  Thus, uncited specimens have to be referred to as original material or duplicates of original material. 

Zuccarini was one of many recipients of specimens distributed by Wallich who generally assigned collection numbers to species rather than to specimens in which a particular specimen number may come from different localities.  For example, Wallich 6054A has been reported from Central Midlands near Kathmandu Valley in Nepal fide Hara et al. (1978) and Anonymous (1913), or “Cachemiro” fide Parlatore (1868), whereas the lectotype—without number—was reportedly from eastern India.  The lectotype was indicated by Zuccarini to have been collected or sent to him in the year 1835, after distribution of Wallich 6054, sometime  between 1831 and 1832 (Anonymous 1913).   It was probably collected in Assam where Wallich was know to have collected during 1835 (Burkhill 1965).  Because the ICBN (Art. 8.2) links the type to a single gathering, isolectotypes cannot be recognized in this case. It should be noted that types have male cones, reddish orange branchlets, non-inflated epidermal cells on abaxial surface of leaves, and 12-15 rows of stomata/band.

Wallich specimens of T. wallichiana with notations of “Kumaon” may be an error in numbering or labeling since collections from “Kumaon” generally belong to T. contorta, whereas Wallich collections without number may indicate uncertainty of taxonomic assignment. 

 

Fig. 9–10: Taxus wallichiana Zucc. Fig. 9 (left): Illustration by Zuccarini in Siebold &
Zuccarini (1843). Fig. 10 (right): lectotype, Wallich s.n., reportedly from E India (M).

 
Typical T. wallichiana is identified by its pale reddish orange branchlets, its persistent  cuspidate bud-scales (Pilger 1916), its linear leaves arcuate near base (Orr 1937; Pilger 1903), its conically shaped seeds (Orr 1937) that often mature on 2nd yr or older branches (in the Himalayas), and its angularly shaped epidermal leaf cells in x-section. Its leaves are further distinguished from those of T. contorta by the adhesive parenchyma cells, and by (11-) 13–18 (-21) rows of stomata/band. Plants from Nepal, West Bengal, Khasia, and Bhutan compare favorably with the type. Those from Myanmar, China, Vietnam, and Malesia generally differ. This variation is discussed below in regard to taxonomic and nomenclatural problems.

Taxus wallichiana has been the name applied to all yews in southeastern Asia (Hu 1964; Pilger 1903 as ssp. (wallichiana); however, de Laubenfels (1988) adopted T. sumatrana for his treatment of gymnosperm taxa in Flora Malesiana. He indicated that several species may overlap in the eastern Himalayas, suggesting that T. wallichiana was outside the Flora Malesiana region, but considering the numerous synonyms and references he provided, one might have also expected more on distinction between T. wallichiana and T. sumatrana (Miq.) de Laub. Taxus wallichiana has largely been ignored by Rehder (e.g., Rehder 1940, 1949) and Hortus Third (Liberty Hyde Bailey Hortorium Staff 1976), while others have mentioned it as a species confined to the Himalayas (Krüssman 1985), or more limited to the northwestern Himalayas (Wilson 1926), or as one of two partially sympatric species predominantly Himalayan in distribution (Silba 1984). Since Pilger (1903, 1916) did not cite any specimens for Taxus in western Himalayas, but indicated T. wallichiana to occur in eastern Himalayas, this omission may reflect uncertainty on his part as he noted there were intermediates to T. baccata.

I do not accept all morphological variation of Taxus in southeastern Asia to belong to a single species (Appendix 1). My interpretation agrees in part with that of Handel-Manzzetti (1929), Florin (1948a), and Hu (1964). They recognized another sympatric species by the lack of papillae on the abaxial leaf midrib, which I consider applicable to a species group typified by T. sumatrana (Spjut 1998b, 2000a, Spjut 2007b). This includes the types of T. mairei, T. speciosa, and T sumatrana and other undescribed species.  However, Kwei & Hu (1974) and Cheng & Fu (1978) recognized intermediates between T. wallichiana (papillose midrib) and T. sumatrana (smooth midrib), and treated the latter as a variety under two illegitimate combinations (T. chinensis var. mairei, T. wallichiana var. mairei), whereas Spjut (1993, 1998b, 2000a) reported other correlative features such as epidermal cells in transverse sections appearing angular in a Wallichiana Subgroup of species (C & E Himalayas to SW China; North America) and elliptical in a Sumatrana Group of species (E Himalayas to Indonesia, Philippines).

The Sumatrana Group is generally found at lower elevations—on mainland Asia, below 1700 m (Hu 1964), or below 1200 m (Li & Fu 1997)—whereas T. wallichiana usually occurs above 2300 m.  Within the Sumatrana Group, I distinguish T. mairei by the acute to obtuse leaves with relatively short trapezoidal, somewhat inflated (mammillose) epidermal cells on an elevated, truncate to channeled midrib as seen on the abaxial surface—indicated in my annotations accompanied by crude illustrations (A, GH, June 1996).  Leaves of T. sumatrana differ by tapering to an acuminate apex and by nearly rectangular shape of abaxial epidermal cells.  Leaves of T. sumatrana var. sumatrana are mostly puckered on drying with revolute margins and a raised abaxial midrib in contrast to those of T. celebica that are relatively flat with a flush midrib.  Taxus speciosa differs from T. mairei only in features of branching and color (in dried specimens), treated as a variety of T. mairei in my annotations. Also, I recognized another species by conspicuous persistent bud-scales at base of branchlets, and by leaves that are rigid, evenly tapered to base and apex (e.g., Fig. 2 in Li 1963), and with a rusty orange color in the herbarium (T. kingstonii Spjut ined.).  Differences in seed shape and color are also evident among these taxa, but taxonomic emphasis on seed characteristics could lead to recognizing more taxa.

The taxonomic and ecological significance of midrib papillae on the abaxial (ventral) epidermal surface of leaves in Taxus was studied by Bertrand (1874), Cheng & Fu (1978), Deryugina & Nesterovich (1981), Florin (1931, 1948a, 1948b), von Frimmel (1911), Kwei & Hu (1974), Orr (1937), and Spjut (1992, 1993, 1998a, 2000a; Spjut in Hils 1993); however, intermediates have been recognized by partially papillose midribs.  These intermediate usually have elliptical shaped epidermal cells in leaf transverse sections and are thus considered to belong to the. Sumatrana Group, in contrast to entirely papillose midribs of the Wallichiana Group or the entirely smooth midrib cells that is characteristic of the Sumatrana Group.  Whether these intermediate represent evolutionary, environmental, or hybrid variants, has yet to be determined.  I suspect all three contribute to variation in leaf anatomy.

Nonetheless, I consider the ancestral type of Taxus leaf to have stomata distributed completely across the undersurface without differentiation of an epidermal midrib. The evidence for this is seen by comparing stomatal features of other taxads with those of Taxus, and by phytogeographical patterns on numbers of stomata rows within the genus Taxus (Spjut 2007a).  The stomata in extant Taxus are always encircled by papillose accessory cells (only partially in T. canadensis), in contrast to other taxad genera. Austrotaxus, for example, has hypostomatic leaves that lack papillae and distinct bands, and stomata are more randomly distributed; Pseudotaxus (Nothotaxus Florin 1931, 1948b) has 23–28 rows of stomata in bands well defined by glaucous cells instead of papillose cells, although subsidiary cells are papillose, and is also ancestral in regard to additional sterile scales in male cones (Florin 1948b; Miller 1988). Within Taxus, particularly T. wallichiana and T. chinensis, stomata are occasionally seen on the epidermal midrib that divides the stomatal region into two bands, extending almost continuously across the midrib in Kingdon Ward 8594 (K) from Assam, and in Hooker & Thomson s.n. (GH) from Sikkim (var. yunnanensis), and stomata may also extend to near the leaf margins in up to 21 rows, whereas in North American plants not more than 11 stomata rows/band have been found (Spjut 1992, 1993, 1998a, 2000a).

Additionally, species that have more conspicuous papillae along cells walls (e.g., T. brevifolia, T. globosa, T. wallichiana) appear less variable in the distribution of papillae on the undersurface of leaves (including juvenile leaves), compared to those species that have papillae more erect on upper surface of cells (e.g., T. sumatrana). This may relate to a gradual evolutionary loss of leaf stomata followed by a reduction in the width of the stomatal region in T. wallichiana, compared to a possible widening of the leaf by addition of cells within the marginal region in T. sumatrana.

The presence of papillae on the undersurface of leaves in the T. sumatrana Group may be of secondary origin—after papillae and stomata became lost. This is evident by a sharp demarcation between the stomata bands and adjacent epidermal cells that are variable in distribution of papillae.  For example, leaves of Wilson 1265 (A, BM, K, S, US) collected from 600–650 m in western Sichuan were found with15–21 stomata rows/band bordered by a partially papillose marginal region with papillae on 6 of the 16–25 cells across. Leaves of three specimens from a related plant grown from seed of Wilson 1265 at the Royal Botanic Gardens in Kew all lacked papillae entirely along an abaxial margin zone of 18–28 cells across, but consistently had 8–10 stomata rows/band. Other related specimens cultivated in the United States for which I received 20 leaves (Phyton s.n.)—from apical buds to 3rd yr branchlets—were found to be relatively constant in the number of marginal cells without papillae—9 cells across—and also in having 16–18 rows of stomata rows/band, but were variable in shape and length of epidermal cells, and in the development of midrib papillae, especially the young leaves. This introduction of Wilson 1265, apparently from Sichuan near Mt. Emei at 600 m and/or Yachou Fu at 600 m, is not T. chinensis as indicated in the literature (Rehder & Wilson in Sargent 1914); however, Wilson 1265 was reportedly collected from three localities (Rehder & Wilson in Sargent 1914), one of which I have identified a specimen as T. chinensis—from western Hubei south of “Ichang,” 600–1300 m.

Taxus wallichiana is also interpreted to occur on Mt. Emei in Sichuan (China) where it integrades with T. chinensis.  Subtle differences in size of bud-scales and color of branchlets make it difficult to consistently separate the two species. These problematical plants may be hybrids between T. wallichiana var. yunnanensis and T. chinensis, and/or possibly another species I recognized by slightly larger and more persistent scales at base of branchlets (T. scutata Spjut ined, inadnot., A).

Species appearing most related to T. wallichiana include T. globosa and T. brevifolia in North America (Spjut 1998b) and two undescribed in Asia. They share character features of conspicuous bud-scales at base of 1st year branchlets, angular epidermal cells in leaf transverse sections, leaves densely papillose on the abaxial midrib with papillae most conspicuous along cell walls, and seeds maturing on 2nd yr or older branches (Wallichiana Species Group Spjut 1992, 1993, 1998b; Wallichiana Subgroup, Spjut 2000a, c).  One in Myanmar (T. suffnessii Spjut ined., type Kingdon Ward 20902 [A, BM]) is distinct for its relatively large persistent bud-scales (2–3 mm long) with a conspicuous midnerve. Another in Yunnan and Sichuan (T. florinii Spjut ined., type from Yunnan,  R.C. Ching 21980, A) is much like T. globosa and T. brevifolia in North America by the large angular epidermal cells in leaf x-sections, and by stomata developing in less than 12 rows/band; it seems to differ from the North American species by the thicker walled epidermal cells.

1b. Taxus wallichiana var. yunnanensis (W. C. Cheng & L. K. Fu) C. T. Kuan, Fl. Sichuan. 2: 215. 1983. Taxus yunnanensis W. C. Cheng & L. K. Fu, Acta Phyto. Tax. Sin. 13 (4): 86, fig. 52, 4–7. 1975. Taxus chinensis (Pilg.) Rehder var. yunnanensis (W. C. Cheng & L. K. Fu) L. K. Fu, Vasc. Pl. Hengduan Mount. 1: 214. 1993. Type: CHINA. Tibet: Zayul, 2100 m, Zhang 916 (holotype: CAF; isotype: PE-leaf fragment! photocopy! http://www.cvh.org.cn/pic/pe/0/00000090.jpg). Topotypes: PE (no other data, leaf fragments!], BM (Kingdon Ward 10398!).

Shrub or tree to 20 m high; branchlets subpinnate, simple to isodichotomously or isotrichotomously divided, yellowish green, reddish orange or abruptly reddish purple in 2nd yr, leafy to base; bud scales persistent, brownish, overlapping in 3–4 ranks, the lower scales adnate, ovate, ca. 0.5 mm long, upper scales thick, incurved, spreading, concave, ca. 1.5 mm long. Leaves ± in two ranks, slightly overlapping in pairs, more evenly spaced along branchlets than in typical variety, lanceolate, acuminate, mostly straight, rarely falcate, 1.5–3.5 (-4.7) cm long, 2.0–4.0 mm wide, 150–250 µm thick, dark glossy green above, pale green to yellowish green below (in dried specimens), slightly convex above to a rounded midrib that forms a channel along the base on the lower half of leaf, nearly flat below to a flush to slightly rounded midrib, plane to abruptly revolute 80-90º near margins; upper (adaxial) epidermal cells mostly rectangular in x-sect., some cells appearing quadrate, occasionally taller than wide, 25 (-50) µm tall, 25–37 (-50) µm wide; lower (abaxial) epidermal cells often similar in size to upper in x-sect. as seen near margin, usually taller than those of var. wallichiana, numbering 7–28 between margin and stomata band, irregularly rectangular, often 3–5× l/w, becoming  longer and more uniformly rectangular near margins, entirely papillose across the abaxial surface, or papillae lacking on up to 6  rows across, midrib cells narrow rectangular, 3–7× l/w; papillae mostly erect, medial in 2–4 opposite rows on midrib cells, medial on marginal cells; stomata bands broader than marginal region, with 13–19 stomata rows/band. Male cones maturing on 1st and 2nd yr branchlets, scales in 4–5 ranks; microsporangia 6–8 (5 fide Cheng), pinkish or brownish. Female cones, 1–2 mm long in bud, scales in 5–9 ranks, basal scale not conduplicate, maturing on 1st or 2nd yr branchlets; seed conical, 4 mm long, 3 mm diam.; sharply pointed at apex, purplish.

Yunnan yew. Distribution: mixed forests types, generally at higher elevations than var. wallichiana, 2100–3500 m; India (Sikkim, Nagaland), Myanmar, China (Tibet, Yunnan), occurring with Larix griffithiana Carrière. and Picea spinulosa (Griff.) A. Henry in the Sikkim region (Rau 1974).  Reported from Sichuan in Spjut (2007b) based on two specimens cited on this web page that were erroneously placed here; however, this variety might be expected to occur in Sichuan.

Representative Specimens—India—Sikkim: Terup, 7000–10,000 ft, Hooker s.n., Herb. Hook. fil., right specimen (GH); ex Hooker fil & Thomson (BM, GH); Tongloo [“immense tall tree with long sparse branches and slender drooping twigs,” “9500-10,000 feet” fide J. Hooker, Elwes & Henry 1906], Kurz s.n. (A). Nagaland: Barail Range, Naga Hills, 28º35’N, 93º55’E, 9-10,000 ft, tree, scattered along summit ridge, Kingdon Ward 7755 (K); “Japuo Range,” 7300 ft, Kingdon Ward 18990 (BM);  “Jakpho,” “Naja Hill,” 8500 ft, Clarke 41238B (K). Myanmar (Burma): Mt. Viatoria, 9000-10,000 ft, tree with weeping habit, smooth almost purplish bark, Kingdon Ward 22819 (BM); Myitkyina Dist., Laikam Fenshuling Rd, 8000 ft, tree 40-50 ft, Kernode 17205 (K). China—Tibet: Zayul, Rong Tö Valley, 8000 ft, spreading tree with brilliant green foliage, amongst deciduous trees on slopes and in gullies, Kingdom Ward 10398 (BM); Delei Valley, 9000 ft, Kingdon Ward 8594 (K); Delei Valley, Chiban, 28º10'N, 96º30'E, Kingdon Ward 8090 (K). Yunnan: [Nur ein Baum ober den Tempeln auf dem] Dji-shan ad boreo-orientem urbis Dali (Talifu), 3200 m, Handel-Mazzetti 6408 (GH); Xangbi Xian, W side of Diancang Shan mountain range, Malultang, vicinity of Chang Shan, mixed broad-leaved evergreen forest, 2700 m, 25º46' 100º01, 1984 Sino-Amer. Bot. Exped. 388 (GH, US); W, Shangschang, above Yangbi, 2700 m, tree to 8 m, 1981 Sino-Brit. Exped. To Cangshan 0419 (A, K); Lung-pan la Champu fung, small tree, 10 ft, forest, fruit gray, C.W. Wang 67412 (A), 67414 (A); Chen-Kang Hsien, ravine, 20 m high, male, C.W. Wang 72417 (A); Kiemiu-ingdi above Yangbi, 3000 m, Sino-Brit. Exped., Cangshan 0227 (K).  [Note: Prior to July 2007, two specimens from Sichuan were mentioned here.  These have always been regarded as T. florinii. It appears that they had been inadvertently placed here].

China—Tibet: Zayul, Rong Tö Valley, 8000 ft, Kingdon Ward 10398 (BM), topotype. Specimen photographed in Oct 1997 (left) and again in April 2005 (right).  The more recent photo shows loss of leaves on lower branch, and an occasional leaf from other branchlets.  Taxus needles can be easily dislodged if specimens are not handled with extreme care.  Loans sent out should enclose each specimen in a sheet of paper that completely covers the specimen.  One loan I received had papers only partly covering each specimen; consequently, the paper would clip leaves as the specimens were moved.  The leaves of var. yunnanensis from the type locality are much like typical T. wallichiana in the furrow on the darker adaxial surface; however, the leaf in x-section appears relatively thin and plane.  Another difference is the abaxial leaf surface has many rows of enlarged marginal cells, 3 of which are smooth and 8 of which are papillose.  The papillae are opposite (and medial), appearing more distant in the type than in other specimens.  The marginal cells are followed by 14 rows of stomata.

China—Tibet: Delei Valley, Chiban, Kingdon Ward 8090 (K).  This specimen appears similar to the type.  Younger leaves appear more furrowed (when dried) on the adaxial surface; the leaf section—from an older leaf—is not furrowed.  As in the type, the abaxial leaf surface lacked papillae on three marginal cells and was followed by 8 papillose cells and 14 stomata rows.  The midrib cells appear narrower.  Papillae are distinctly medial, in a single file on narrow cells, and in opposite rows on wider cells.  The leaf mesophyll is illustrated to have a reticulate arrangement of bone-like parenchyma cells with rounded intercelluar spaces.

 

 

 

 

 

 

 

 

China—Yunnan: Shangschang, above Yangbi, 2700 m, 1981 Sino-Brit. Exped. to Cangshan 0419 (A). Top left specimen with lower color photo shows reddish midrib and greenish stomata band.  Observe that papillae are marginal but opposite, such papillae are usually medial.  This character attribute is intermediate to T. chinensis. Observe also the flattened (plane) leaves, appearing lanceolate in shape. This is in contrast to var. wallichiana that has strongly curled leaves, appearing compressed laterally so that the adaxial midrib is furrowed.  Observe also dark persistent bud-scales at base of branchlets in lower photo and seed on 2nd yr branchlets in upper right photo.

 

 

 

 

 

 

 

 

China—Yunnan: Dali (Talifu), 3200 m, Handel-Mazzetti 6408 (A). Three color prints and packet with author's sketch are attached to this specimen. This specimen differs from the typical form in the leaf shape, which is more like T. chinensis than T. wallichiana.  The dark colored branchlets, the persistent scales at base of branchlets, and the large red epidermal cells—as shown in lower photo (25 µm tall and wide)—are characteristics of T. wallichiana.  The medial opposite papillae on the abaxial midrib—as seen in the top left photo—further differentiates this as T. wallichiana var. yunnanensis.  The top right photo shows a stomata band that is also much like T. chinensis, and marginal cells enlarged only in several rows; the packet sketch indicates 7 marginal cells followed by 13 rows of stomata.

 

India-Nagaland: Barail Range, Naga Hills, 9000-10,000 ft, Kingdon Ward 7755 (K).  This specimen differs from the typical form in the lack of enlarged epidermal cells along  the abaxial leaf margin.  Otherwise, it agrees with var. yunnanensis in shape of leaf in x-section, in having 4 rows of smooth marginal cells followed by 14 rows of papillose cells and in the 14 rows of stomata. The papillae were noted to be opposite and very prominent, even occurring in two rows on narrow midrib cells.

 

 

 

 

 

India-Nagaland: “Jakpho,” “Naja Hill,” 8500 ft, Clarke 41238B (K).  This specimen differs from the typical form by the paler orange instead of dark purplish colored branchlets.  The leaves appear similar to the type in shape and anatomy. The abaxial leaf margin was noted to have 3 rows of smooth cells followed by 13 rows of enlarged papillose cells, 11/12 stomata rows, and 12 rows of rectangular midrib cells.  As in the type, the papillae appear relatively small in size and distant and opposite each other.  The leaf mesophyll is shown to have a reticulate network of parenchyma cells with rounded intercellular spaces; in the upper right hand corner is a more detailed drawing of the parenchyma cells removed from the mesophyll region.

Myanmar: Myitkyina Dist., Laikam Fenshuling Rd, 8000 ft, Kernode 17205 (K).  This specimen has leaves shaped more like specimens from Yunnan than from the type locality in Tibet.  However, the leaf epidermis is much like the type; the abaxial surface has 3 rows of smooth cells followed by 10 rows of enlarged papillose cells and 12 stomata rows.  The papillae are medial, opposite and distant.  The mesophyll parenchyma cells appear to represent a distinct pattern not seen in other species, but no taxonomic distinction is made for leaf mesophyll here as this character is often difficult to evaluate in dried specimens.  Also noted is the sharp contrast in color between the red adaxial epidermal cells, and yellowish to yellowish green stomata and yellowish abaxial midrib.

China—Tibet: Delei Valley, 9000 ft, Kingdon Ward 8594 (K).  This specimen differs slightly in the epidermal cells not being sharply quadrangular.  The abaxial leaf surface was noted to have an olive green color with little differentiation in  midrib, margin and stomata band regions.  The upper right corner of the packet shows a sketch of the bone-like mesophyll parenchyma cells.

 

India—Sikkim: Terup, 7000–10,000 ft, Hooker s.n. (GH), packet illus below drawn from specimen at K.  This specimen is remarkably similar to the one above collected by Kingdon Ward 7755 from Nagaland.

 

 

China—Yunnan: Diancang Shan mountain range, Malultang, vicinity of Chang Shan, 2700 m, 1984 Sino-Amer. Bot. Exped.388 (GH).

 

 

 

China—Yunnan: Kiemiu-ingdi above Yangbi, 3000 m, 1981 Sino-Brit. Exped. 227 (K)

 

 

 

 


China—Yunnan: Chen-Kang Hsien, ravine, 20 m high, male, C.W. Wang 72417. Intermediate: Papillae noted be marginal on midrib cells, but appearing medial on marginal cells. Treated previously under var. wallichiana.
 

T. yunnanensis, photocopy and photo of isotype at PE

 

 

  

Taxus yunnanensis has been confused with T. wallichiana in the Flora of China (Cheng & Fu 1978). The authors had evidently considered the type for T. wallichiana to represent the species mainly in NW Himalayas; consequently, they described T. yunnanensis—indicating it was found in eastern Himalayas (Bhutan, Tibet, Myanmar) to Yunnan and Sichuan (Cheng et al. 1975; Cheng & Fu 1978). Later, it was reduced to a variety of T. wallichiana as cited above, and more recently placed in synonymy (Li & Fu 1997), although it had been included in synonymy by de Laubenfels (1988) under his broadly circumscribed T. sumatrana.

Most specimens I annotated T. yunnanensis (A, GH, July 1996; BM, Oct. 1997; Spjut 1998b) were from Yunnan and Sichuan. They were distinguished from typical T. wallichiana by the leaves appearing slightly wider (nearly lanceolate), more evenly distributed, less markedly curved above and paler green below than above, and having medial papillae on the abaxial epidermal cells.  At the time I had seen only leaf fragments of a type—from Tibet near the border with Myanmar and India; it differed from the type of T. wallichiana by the abaxial surface having a broad region of large epidermal cells with medial papillae between the margins and stomata bands. These features were seen more often in yew specimens from Yunnan and Sichuan than in those from northeastern India. Later, I received a B/W photocopy of a PE isotype from Dr. Z-y. Cao who had earlier sent me leaf fragments of topotypes, and found that the leaf arrangement and shape compare closer to the type of T. wallichiana than to specimens from Yunnan and Sichuan. Thus, plants most typical of this variety as seen in northeastern India and nearby Tibet are intermediate forms, distinguishable only by leaf anatomical characters. For this reason T. yunnanensis is reduced to a variety.  Nevertheless, it is important to differentiate these and one other related species under study (T. florinii Spjut ined) in order to distinguish the North American species (T. brevifolia, T. globosa) from their Asian relatives; otherwise, they would have to be included under T. wallichiana.

2. Taxus contorta Griffith, Not. Pl. asiat. 4: 28. 1854 (“Taxus contortus? Vide Itinerary Notes, p. 351, No. 116”.  See also Itin. pl. Khasyah mts., II: 351. [1847-] 1848 [Book III,
Chapter II, “Affghanistan Flora, Second year Kafiristhan.116. Taxus?” “Arbor, foliis alternis linearibus compressis, sulcato univeniis basi ½ tortis. Brought from Kafiristhan with the preceding [Pinus], the undersurface of the leaves subsequently becomes uppermost from torsion of the base. The change takes place gradually judging from the slight obliquity of young leaves.  Stomata blocked up, with a brown curious cuticular substance.”]).  TYPE: AFGHANISTAN. W of Kabul, “Bharowul, in woods, 7000–7500 ft” (locality data from Griffith nos. 112-114 in Itin. pl. Khasyah mts, collected during 1839–1841), Lectotype—Griffith 5002 at K! (lower right specimen of three on one sheet, Fig. 11, the other two specimens evidently part of a separate single collection with handwritten note on a label indicating bark wasText Box: Fig. 11. Taxus contorta, lectotype used in a tea in Ladakh, det. by Spjut as T. contorta, designated by Spjut 2007).  Note that both publications by Griffith have to be applied together for valid publication.

 

Photocopy of relevant pages from Griffith, Notulae Plantas Asiaticus, 1854.

 

Taxus orientalis Bertoloni, Mem. Acad. Sci. Bologna ser. 2, I, 229, pl. 2 (1862); Misc. bot. 23: 17, Tab. 2 (shown here). 1862, and holotype. 

 

Taxus fuana Nan Li & R. R. Mill in Li & Fu, Notes on gymnosperms I. Taxonomic treatments of some Chinese conifers. Novon 7: 263. 1997 (Nov.).—TYPE: CHINA. Tibet (Xizang): Jilong, 3000 m, Qingzhang Expedition 7032; holotype PE!

Taxus orientalis Bertoloni, Mem. Acad. Sci. Bologna ser. 2, I, 229, pl. 2 (1862); Misc. bot. 23: 17, Tab. 2. no specimens cited. TYPE: northeastern India, western Sikkim, 8,000 ft (Holotype: BOLO [leaf fragments!]).

 
2a. var. contorta. Ultimate branchlets yellowish green, gradually reddish or yellowish brown; bud-scales persistent or semi-persistent at base of current growth in 3–4 ranks; these thick, greenish to brownish, the lower scales paleaceous, ovate or deltoid, concave, acutely folded along a prominent midnerve, ca. 0.5–1 mm long, the uppermost cucullate, ca. 1 mm. long. Leaves closely overlapping, linear and sharply apiculate, straight to falcate, 1.5–3.5 cm long, mostly ca. 2 mm wide, 350–500 µm thick, olivaceous and convex above to a rounded midrib that forms a slight channel along each side at base, olivaceous or yellowish green and plane to slightly concave below to a flush or slightly rounded midrib, abruptly revolute near margins, or only slightly revolute near margins; upper (adaxial) epidermal cells in x-sect. elliptical to slightly angular in plants from Nepal (probably hybrids with T. wallichiana), 10–15 µm tall and 20–35 µm wide; lower (abaxial) epidermal cells quadrate in up to 6 rows nearest margins, becoming long fusiform to long rectangular towards stomata bands, not always distinct from those in stomata bands, 3–10× or more l/w, 8–12 µm tall, 10–25 µm wide, prominently papillose to within 4–6 (-8) cells of the margins; stomata bands greenish, or yellowish green, narrower than the marginal region, with (5-) 7–8 (-9–11) rows of stomata, the stomata counts generally lower in the NW Himalayas and higher in Nepal; palisade parenchyma of 1 row, 50–70 µm long; spongy parenchyma cells elliptical, resinous, with sclerified walls, loosely connected, falling apart when leaves of herbarium specimens are soaked and sectioned. Male cones abundantly produced near ends of branchlets, their buds globose, ca. 2 mm diam. Female cones maturing on 1st and 2nd yr branchlets; seeds subcylindric to obconic, ca. 6 mm long, 4 mm diam., abruptly tapering near apex.

West Himalayan yew. Distribution: Mixed coniferous-hardwood forests of W Himalayas, 2300–3500 m; Afghanistan, Pakistan, India, W Nepal, China (SW Tibet). Noted to be common in the Garhwal and Kumaon regions at elevations near 8500 ft (Gamble 1922; Gordon 1875) where clouds often hang in oak-conifer forests of Quercus semecarpifolia Sm., Abies pindrow (D. Don) Royle, and Rhododendron arboreum Sm. (Freitag 1971; Rau 1974). In the Uri Range closely associated with Abies pindrow-Picea smithiana (Wall.) Boiss. forest (Sapru 1975), a vegetation type common to the higher ranges in the W and C Himalayas of India and Nepal (Champion & Seth 1968; Rau 1974). In the Kumaon and Nepal regions mostly on N side of the Himalayas in hemlock (Tsuga dumosa (D. Don) Eichler) forests with spruce (Picea smithiana) as a common associate (Rau 1974), especially near Rara Lake in W Nepal (Stainton 1972).

Representative Specimens—Pakistan: Between Gotchbok and Kubkot Valley, 2750 m, Sinnott et al. 146 (K); Punjab Province, near Rosenhiem, Murree, Rodin 5313 (US); Murree, 7000 ft, Stewart 15343 (NA, US), Sprague 730 (K). India—NW Himalaya: Punjab, Kulu, above Bandrole, elev. 8000 ft, Koelz 10285 (A, NA); near Kulu, Bushreo Pass, Koelz 3119 (US); above Jaurah, Tehri, Koelz 10385 (NA); Kashmir, Pahlgam, 7000–10,000 ft, tree, Stewart 5931 (A), 8414 (A, NA, PH, US), 12001B (A), 2600 m, Heybrook 29 (K); Kashmir, Sukhi across the Bamsuru and Chaia Pass to Khdrsali (Passes between the Bhagiratti and Jamma Valley), 9000–15,400 ft, Schlagintweit 8941 (GH); Kashmir, Lida Valley, Mukiji (K); Bashahr, Uri Forest, 20 Jun 1890, J.H. Lace 301 (A); NW of Srinagar, ex Herb. Schlagintweit s.n. (PH); Sonamarg, 10,000 ft, Stewart 7374 (PH); Gulwarg, 7000–10,000 ft., Stewart 10663A (PH); Chamba, Kalatop Reserve, Pergamma Bathri, 8500 ft, 12–4-1920, R. N. Parker s.n. (A); Dharmkat, Dharmsala, Stewart 1938 (BH, PH); Siwalik and Jaunsar Div., 10,000 ft, Laig Raus (P); Baltal to Nunner, ex Herb. Schlagintweit 4795 (P); Kujiar, Chunuba, 7000 ft, 2 Oct 1874, C.B.Clarke s.n. (A, P); Chumba, Pengelly s.n. (K); Panwanle Kanta, 9500 ft, Sahni 21664 (BH), 21669 (BH); Bureah, 11,000 ft, Kenyoer & Dugeon s.n. (PH); Tehri above Jaurah, Koelz 22084 (NA); Garhwal to Lake Hemkund, 3200 m, Rau 31770 (A); Kumaon, Wallich 6054/B (BM on three sheets, K, p.p.; M, p.p.; P on three sheets, p.p.; K, M & P also have Wallich specimens of T. contorta numbered 6054A); Kumaon, Dwali? 8500 ft, ex Herb. Falconer 1000 (GH, P, S). Matiana Hill, ex Herb. Reg. Bot. Calcutta (BH). Nepal: Dhotar, 9600 ft., Polunin et al. 1353 (BM), Chankeli Range, 8000 ft, Polunin et al. 432 (BM); W of Jumla, Belas Gaejigeth, 10,000 ft, Polunin et al., 5050 (BM); Lete, S of Tukucha, 8000 ft, Stainton et al. 734 (BM); Chingnon, N of Tukucha, Gadaki Valley, 10,000 ft, Stainton et al. 7832 (BM); 5616 (BM); Dhaulagiri Zone, 2405 m, Mikage et al. 9550282 (BM); Marayandi Khola, Ottba et al. 8311066 (BM). China Tibet (Xizang): Gyirong County Bangxing, 3000 m, Li-Chen Shu-kun, Du 589 (PE); Gyirong County, Shenyang, 3100 m, Tibet Team 13 (PE); in several villages Gyirong County District Gilon, Jisonglin geopolitical hillside fire, 3000 m, Qinghai-Tibet Team 7032 (PE, evidently an isotype but not indicated as such).  Note: citation of PE specimens from virtual online herbarium, spelling as it appeared on that site.  Additional material (needles) received by Spjut from Dalian Inst. Chem. Physc, 30 Apr 2007, reportedly collected from JiLong, 2750 m, JiLong Forestry Bureau staff expert (CAS, wba [needles]).

 

India—NW Himalaya: Left—Punjab, Kulu, above Bandrole, 8000 ft, Koelz 10285 (A).  Himachal Pradesh. Right—Bashahr, Uri Forest, 20 Jun 1890, J.H. Lace 301 (A).  These specimens are typical of the species in the distichous arrangement of the leaves spreading mostly ~45º.  Branchlets appear to be pendulous. The most distinctive character feature is the rounded parenchyma cells is the leaf mesophyll.  These often appear like red egg shells.  They are loosely contained within the mesophyll, and fall out when leaves are sectioned.

Nepal: Chankeli Range, 8000 ft, Polunin et al. 432 (BM).  Left—specimen typical of the species, right—close-up of branchlet showing scales, mostly in a single series at base of branchlets, often not persistent; det. T. contorta by Polunin et al..

 

 

 

Nepal: Dhotar, 9600 ft., Polunin et al. 1353 (BM).  Differs slightly from the typical form in that leaves spread more at 60º; annotated T. angustifolia by Franco.

 

 

 

 

India: Jaunsar  Dist., 10,000 ft., Gamble 23507 (K). In this specimen leaves appear more distant and radial in arrangement.

 

 

 

 

 

India—Siwalik and Jaunsar Div., 10,000 ft, Laig Raus (P).

India: Kumaon, Dwali? 8500 ft, ex Herb. Falconer 1000 (GH).

 

 

Kashmir, Pahlgam, 7000–10,000 ft, tree, Stewart 8414 (A).

 

 

India—Chamba, Kalatop Reserve, Pergamma Bathri, 8500 ft, R. N. Parker s.n. (A); annotated T. orientalis.

 

 

India—Tehri above Jaurah, Koelz 22084 (NA).

 

 

 

Wallich s.n. & locality data, with T. wallichiana (P).

 

 

 

Pakistan: Between Gotchbok and Kubkot Valley, 2750 m, Sinnott et al. 146 (K), annotated T. wallichiana by Farjon (Mar 1996).

India: Chumba, Pengelly s.n. (K); annotated T. fuana by Fu & Li Nan.

 

 

Taxus contorta is one of the easiest yew species to identify. The relatively long, straight, narrow leaves are generally crowded along stems in nearly two ranks that in the typical form generally do not spread more than 60° from branchlets. The leaf mesophyll contains distinctive parenchyma cells (idioblasts) that appear reddish in dried specimens (after soaking in water).  These cells occur predominantly across the mid region of the leaf mesophyll and around the diffusion area of the vascular bundle.  They are not sclerenchymatous, but appear the reddish striations appear to be resinous deposits on cells walls.  Rao and Malaviya (1965) described what they called “osteo-sclereids” in leaves of one of four varieties of T. baccata they reportedly studied; however, their material reportedly lacked cones, and their illustrations of leaf sections showing sclereids are reminiscent of what I have observed in Asian species of Torreya.

Taxus baccata has similar idioblasts as seen by the spherical shape and dark color, but do not show the sclerified (striated) walls, and do not fall apart when sectioned.  The Cuspidata Alliance generally has a leaf mesophyll largely of loose spherical to ellipsoidal cells connected together by short cylindrical cells that are without idioblasts. 

Taxus contorta is more related to T. baccata (lectotype based on “Hort. cliff. 464”; Jarvis et al. 1993, Clifford Herb., BM!) than to T. wallichiana by the relatively low number of leaf stomata rows/band—usually 7–8, by the ellipitical epidermal cells as seen in leaf x-section, and by characteristics of leaf mesophyll cells as just described. The leaf mesophyll of T. wallichiana in contrast usually has periclinally oriented, elongate cells connected in a skeletal-like net; in longitudinal sections these cells do appear like bones. Additionally, T. baccata exhibits more variation in Europe than T. contorta in the Himalayas in branching, leaf arrangement and leaf anatomy. Of particular relevance is the occurrence of papillae on the abaxial midrib of leaves—that in T. baccata can be densely papillose (e.g., lectotype) or entirely smooth (e.g., Curic s.n., from Bosnia, K), whereas T. contorta always has a densely papillose midrib.

The close relationship between the European T. baccata and Himalayan T. contorta was recognized by Handel-Mazzetti (1929) and by Florin who in his annotations of specimens at Stockholm (S) regarded it as a subspecies of T. baccata in which he had adopted the epithet from T. orientalis Bertol., a later name.

Other botanists have independently recognized T. contorta as distinct from T. baccata and T. wallichiana, but by names that are not always in accordance with the ICBN. For instance, Handel-Mazzetti (1929) correctly realized that T. wallichiana was based on Wallich 6054A, but referred the northwestern Himalayan yew to T. orientalis.  He was also aware of T. contorta, which he referred to as a nomen nudum; however, Griffith (1854) referred back to his earlier 1848 publication as referred to above; thus, T. contorta is not a nomen nudum (Art. 32.3, 32.4, 34.1), and predates T. orientalis Bertoloni (1862). Franco (1964), who reviewed Taxaceae for Flora Europaea, also recognized the west Himalayan yew (T. contorta) as a distinct species, but he annotated specimens (BM) by another name (T. angustifolia Franco, ined., dated 1956) that if published would have been illegitimate; more recently, Nan Li & R. R. Mill (Li & Fu 1997) reached a similar conclusion, but did publish their superfluous name, T. fuana. Occasional collections by Polunin et al. (e.g., No. 432, BM) had been correctly determined, while most herbarium collections of this species have been misidentified T. wallichiana.

It is not clear to what extent Wallich and Griffith had distinguished yews in the Himalayas. Wallich’s (1826) Tentamen Florae Nepalensis recognized only one species, determined as T. wallichiana by Zuccarrini (Siebold & Zuccarini 1843); however, Wallich specimens of Taxus numbered 6054, differentiated by letters A-E, suggest they were distinguished—at least by collectors and location, and may include an annotation T. virgata Wall. (nomen nudum), which I have identified as T. wallichiana (Blinkworth s.n. BM, reportedly from Kumaon, but probably from Nepal), or T. baccata (young shoot on sheet with 3 other specimens of T. contorta, Wallich 6054, ex Herb. Gordon, with “b” indicated lightly in pencil, K; probably added for comparison).  Most Wallich 6054A (from Nepal) belong to T. wallichiana, while most Wallich 6054B (from Kumaon) are T. contorta. Griffith, who worked with Wallich on occasion (Burkhill 1965), also assigned mixed collections of Taxus to the same number with different data; the type, for example is from Afghanistan, but other labels with this number (Griffith 5002) indicate the specimens were collected in the eastern Himalayas. Griffith (1854) recognized possibly two species from Bhutan, distinguished by “axillary” and “terminal” “inflorescences” and “3. Taxus contortus?” by reference to his collection from Afghanistan. I have noted that three species of Taxus are represented in Griffith collections.  Similarly, J. D. Hooker may have considered there were three species of Taxus in India as evident by a specimen in the Gray Herbarium with three different species (T. contorta, T. kingstonii, T. wallichiana) all on one herbarium sheet (J. D. Hooker 77, 87, GH).

Although T. contorta appears quite distinct from T. wallichiana, hybrids seem evident by the respective higher and lower counts of stomata rows where geographical ranges of these species overlap—in central and east Himalayas (Spjut submitted).  This includes the type for T. orientalis (BOLO!)—from Sikkim.  In several leaves studied of the T. orientalis type, the parenchyma cells were found to be those of the T. contorta type, whereas the slightly larger epidermal cells (20-25 µm tall, 25–35 µm wide) along with the higher stomata counts (10–11 rows/band) indicate affinity to T. wallichiana, whereas the absence of bud-scales at the base of branchlets, and the strongly revolute linear leaves (illustrated by Bertoloni, 1862) are other features I associate with T. contorta.  Specimens of T. wallichiana var. yunnanensis from Sikkim were found to have stomata in 13 rows (Kurz s.n. A), or 14 rows (e.g., J. D. Hooker & Thomson A, GH, K).

2b. Taxus contorta var. mucronata Spjut, J. Bot. Res. Inst. Texas 1(1): 256. 2007. Taxus mucronata Spjut ined. (A, BM)—Type: BHUTAN (Eastern). Ha: 27º22' 89º18', 9,000 ft, tree 15 ft—11 Apr 1949, Ludlow et al. 16035, with male cones (holotype A! designated June 1996; isotype BM! in adnot., Oct. 1997).

Tree to 3 m or more; leaves sharply bent at base of blade, 1.5–2.5 cm long, ca. 2 mm wide; abaxial epidermal cells up to 23 across the margin, irregularly quadrate in up to 6 rows nearest the margin, becoming long fusiform to rectangular towards the stomata band and on midrib, irregular in width, mostly 3–7× l/w, papillose on more than half of the marginal cells—to within 8 (-5) cells across from margins and entirely on midrib, the papillae positioned medially in 1–2 rows on each cell; stomata bands greenish, or yellowish green, narrower than the marginal region, with 9–11 rows of stomata; palisade parenchyma of one long row of cells and a much shorter second row; spongy parenchyma cells nearly globose, many sclerified and resinous. Male cone scales 4–5 seriate; sporangiophores 8, united into a ribbed column ca. 2 mm long, thickened at apex of column, separating into 8 umbrellalike segments, each with 5–8-cuculately lobed microsporangia ca. 1 mm diam. Seed in one specimen globose, reddish.

Mucronate-leaved yew. Distribution: Upper forest region, 2300–3100 m; Nepal, Bhutan.

Additional Specimens—Nepal: Dobremez 2106 (BM); Marayandi Valley, 3100 m, Wraber 514 (BM); ridge S of Bhahwe Sekh, 9000 ft, Polunin et al. 1873 (BM); Dhawalagiri Zone, Mustang Dist., Ghasa, 2405 m, Mikage et al. 9550282 (BM).

 

Taxus contorta var. mucronata. Illustration in Cheng et al. (1975) and Cheng and Fu (1978) that was referred to as Taxus wallichiana; however, in Li & Fu (Nov. 1997) this was renamed to T. fuana Nan Li & R. R. Mill along with other specimens cited as “paratypes” from the NW Himalayas that correspond to var. contorta. In the present paper, T. fuana is reduced to a synonym of T. contorta.  In China it is reported only from Jilong Xian in SW Xizang (Tibet).  This illustration, reportedly drawn by Liu Chunrong was thought to be similar to the type, but it is not. The illustration was redrawn in the later edition of the Flora of China.

 

 

 

 

 

 

 

Taxus contorta var. mucronata.  Bhutan: Eastern: Ludlow et al. 16035.  Holotype for Taxus mucronata (A), designated by Spjut in June 1996.  Photo of illustration attached to specimen.

 

 

 

 

Taxus contorta var. mucronata.  Bhutan: Isotype for Taxus mucronata at BM showing annotation label by Spjut, dated 21 Oct 1997.

 

 

 

 

 

 

 

 

 

 

 

 

Taxus contorta var. mucronata.  Nepal: Karayandi Valley, Hanang, between Pinang and Chaug, 3100 m, Wraber 514 (BM).  A temporary label was provided indicating a leaf fragment was taken.  The species status of this taxon was based on a combination of features—sharply reflexed leaves, relatively short leaves, a relatively wide marginal region of cells on abaxial surface, and higher stomata count (compared to other specimens from NW Himalayas)—in only one specimen from Bhutan (GH: holotype).  However. another specimen from Nepal at BM was found to have these same features, including the marginal cells, parenchyma cells, and stomata count. 

Taxus contorta var. mucronata.
Intermediate

Nepal: Dhawalagiri Zone, Mustang Dist., Ghasa, 2405 m, Mikage et al. 9550282 (BM).  This specimen differs from the Bhutan specimens above in having a relatively narrow abaxial leaf margin, 4 cells wide, and by leaves tapering to an acute, apiculate apex. 

Taxus contorta var. mucronata.  Nepal: Dobremez 2106 (BM).

Taxus contorta var. mucronata
Intermediate

Nepal: 9,000 ft. Polunin et al. 1873 (BM, det. by Polunin et al. as T. contorta.  The relatively longer leaves of this specimen, appearing more acute near apex (less abruptly tapered), suggests var. contorta, whereas the conspicuous mucro agrees with var. mucronata. 

Taxus contorta var. contorta
Intermediate

Nepal: 8500 ft, Gardner s.n. (BM).  The relatively long leaves of this specimen favors var. contorta whereas the wide divergence from branchlets agrees more with var. mucronata.

I annotated one specimen from the Arnold Arboretum Herbarium, Taxus mucronata Spjut (ined.) in June 1996, and also designated it as type. Other specimens at the Museum of Natural History in London (BM) were later discovered and similarly annotated (Oct. 1997). Although Taxus fuana was not described until later (Nov. 1997), all specimens I saw also at K bearing the annotated name T. fuana (by Li and Mill) belonged to var. contorta, not var. mucronata as I have recognized it here, whereas specimens I annotated T. mucronata Spjut ined. were not annotated by Li and Mill. However, the illustration in Cheng et al. (1975) and in Cheng and Fu (1978), which I had  erroneously referred to as drawn from the type from Tibet, referred to by Li and Mill (in Li & Fu 1997), undoubtedly belongs here even though Nan Li and R. R. Mill in my opinion did not distinguish this taxon, but it is not a type as I have recently discovered; therefore, T. fuana is now treated as a synonym of T. contorta var. contorta.  All other (eight) specimens they cited, referred to as “paratypes” (from India, Kashmir, Pakistan, Nepal) belong to var. contorta.   Farjon (1998)—by listing the species as known only from the type locality—excluded T. contorta var. mucronata.  However all material I have seen from Tibet on the PE website belongs to var. contorta as might be expected since Fu et all. (1999) report the occurrence of T. contorta in China (as T. fuana) only in SW Tibet.

This variety is distinguished from the typical variety by the relatively shorter and more sharply reflexed and abruptly apiculate leaves.  Other differences are seen on the abaxial leaf surface having a smooth marginal border of 5–8 irregularly quadrate epidermal cells, and 9–11 stomata rows per band; however, occasional plants from Nepal are difficult to assign to either variety, which is why it is regarded only as as a variety.  A geographical analysis of character traits of Taxus contorta revealed that plants with more widely spreading leaves, and with more stomata and wider leaf margins, occur in the eastern range of the species where it is sympatric with T. sumatrana and T. wallichiana.  Also, where these species appear sympatric, T. wallichiana was found with lower stomata counts.  Thus, it would appear that the merging of these species characteristics is the result of introgression.  However, it might be added that the shorter and more sharply reflexed leaves are features that are related to T. chinensis and T. umbraculifera.

 

3. Taxus chinensis (Pilg.) Rehder, J. Arn. Arb. 1: 51. 1919. Taxus baccata L. [ssp. cuspidata (Siebold & Zucc.) Pilg.] var. chinensis Pilger, Pflanzenreich IV, 5: 112. 1903. Taxus cuspidata Siebold & Zucc. var. chinensis (Pilg.) C. K. Schneider ex Silva Tarouca, Freiland-Nadelgehölz. 276. 1913. Taxus wallichiana Zucc. var. chinensis (Pilg.) Florin, Acta Hort. Berg. 14, 8: 378. 1948. Type: CHINA. E Sichuan: Wushanhsien, 2000–3000 m—selected partially by Rehder & Wilson in Sargent, Pl. wilson. 2: 8. 1914,“Henry 7097, 7155, type,” and by Florin (1948a, l.c.), “Henry 7155”; here further clarified by specimens in Harvard University Herbaria, 2 sheets, one in A indicated as “type” by Hu, another in GH annotated as “isotype” by Hu. —Lectotype: sheet in A! bearing accession # 18682, with seed (isolectotypes: BM! E, GH! K! (Fig. 12) S [fragment], US!).  Other original materialText Box: Fig. 12. Taxus chinensis, isolectotype (K). (syntypes): Henry 6913, Farges 128.

Taxus baccata L. var. sinensis, Henry, Elwes & Henry, Trees Gr. Brit. and Irel. 1: 100. 1906. Type: CHINA. Same locality as for  T. baccata var. chinensis; lectotype here designated: Henry 7097  
at E. Isolectotypes: A! BM! P! US!  Nomen illegit. (ICBN Art. 53.3, Ex. 9).

 
Ultimate branchlets yellowish green, gradually yellowish red, or yellowish brown, or dull reddish orange with age; bud-scales occasionally persistent on 1–2nd yr branchlets, wart like or squamulose, not overlapping, or overlapping only slightly, ca. 0.3–0.8 mm long. Leaves mostly green, or turning reddish when dried, narrowly to broadly oblong, 1–2 (-2.5) cm long, 1–3 mm wide, 0.25–0.5 mm thick, strongly convex above to a rounded midrib, plane to slightly concave below to a rounded midrib; upper (adaxial) epidermal cells in X-sect. usually elliptical, occasionally angular, typically wider than tall, 10–25 µm tall and 25–40 µm wide, occasionally 25–30 µm tall and 35–40 µm wide, thick-walled, not inflated; ventral (abaxial) epidermal cells not as tall as those on upper surface, reddish, 5–12 µm tall and 15–25 µm wide, short to long rectangular, 1–5 (-7)× l/w, more irregularly quadrate near margins, usually papillose entirely across midrib, and to within 4–12 cells from margins; papillae egg-shaped, positioned marginally (mostly along cell walls) in 2–3 alternate rows, or occasionally medially on midrib; stomata in yellowish green to yellowish orange bands broader than adjacent marginal region, 11–19 (-21) rows/band; palisade parenchyma cells usually of 1 row, or 2 rows on young leaves, 50–150 µm long. Male cones ovoid in bud, 2–3 mm wide and 4 mm long, maturing on 1st–2nd yr branchlets. Female cones subcylindric, to 2 mm long in bud, maturing on 1st–2nd yr branchlets; seeds subglobose, or conical, slightly angled, to 5 mm long and 4 mm wide, tapering to apex from mid region.

China yew. Distribution: Forest, or forest margins, or open scrub, “under rocky cliffs,” “often among bamboos,” generally 1000–2800 m, mostly China (Guangxi, Gansu, Yunnan, Sichuan, Guizhou, Hubei, Anhui, Zhejiang), one collection from Vietnam. Reported also at elevations as low as 150 m (Hu, 1964). In Sichuan found more in the drier “mixed mesophytic forest” or “transitional zone” to an evergreen oak forest, in contrast with T. wallichiana occurring more in hemlock-spruce-fir forests (Wang 1961).

Representative Specimens—Vietnam: Hoa Binh, Mai Chu, P Co, 900–1500 m, with Podocarpus and Pinus, Hiép & Chan 405 (P). China—Sichuan: NE, Tschen-kuu-tin Dist. (Chenkouting, Florin 1948a), Farges 128 (K, P); Tschsianling, 2600 m, H Smith 10398 (BM, S); Kwang-yun Hsien & vicinity, 1800 m, outside cottage, tree, F. T. Wang 22602 (A); W of Wen-chun Hsien 2450 m, streamside, F. T. Wang 21114 (A); E(O-)mei-hsien, Mt. Emei, W. K. Hu 8176 (A), 8243 (A, US), 8786 (A); Yu-shih Liu 1136D (A, NA); Yachow 1600 ft, T.C. Peng 502 (A); 2000 m, F. T. Wang 23656 (A, P); mt. slope, 2600 m, T. T. Yu 667 (A); mt slope among woods, 2500 m, T. T. Yu 869 (A); T. C. Lee 3237 (A), 3347 (US); W.P. Fang 18420 (A); morph from Mt. Emei similar to T. baccata var. adpressa: W. K. Hu 8177 (A), 8497 (A), 8542 (BH); T.C. Lee 4445 (A), 4500 (A), Chiao & Fan 464 (A, K, P, US), W. P. Fang 15128 (A), 15940 (A), 16082 (A), 18310 (A), L.Y. Tai 1117 (A); S. Wushan, ravine, Wilson 624 (A, K); W of Wen-chuan Hsien, 2800 m, ridge of thicket, F. T. Wang 20993 (A). Hubei (Hupeh), Western: Shennongjia For. Dist., 31º30’N, 110º30’E, NE of Guanmenshan along the S side of the Shicao river, 1150 m, Sino-Amer. 1980 Exped. 777 (A); 31º30’N, 110º30’E, S of Jiuhuping Forest Farm along Jizigou canyon bottom, 1900 m, Sino-Amer. 1980 Exped. 1540 (A); vicinity of Shibapan, 1850 m, Sino-Amer. 1980 Exped. 1824 (A); Shenlungkai, Cho 76099 (A); Henry 6913 (BM, K, US). Yunnan: Ta-hon-shan near Ta-koo, NE of Likiang Snow Range, by stream in forest, K. M. Feng 630 (A). Guizhou (Kweichow): Cavalerie & Foriupat 2604 (P); Yinjiang Xian, vicinity of Xiapingsho on the W side of the Fanjing Shan Mt. Range, 1100-1400 m, Sino Amer. Guizhou Bot. Exped. 1854 (GH). Anhui (Anhwei): Southern, Clas Hara Shan, R-C Ching 2622 (A). Guangxi (Kwangsi): 2110 m, Steward & Cheo 947 (BM, P).  Zhejiang (Chekiang): Siachu, open cultivated hilltop, 2600 ft, rare, tree 50 ft, 1.2 ft dbh, R- C. Ching 1676 (P).

 

China—E Sichuan: Wushanhsien, 2000–3000 m, Henry 7097 ((A), Proposed isolectotype for T. baccata var. sinensis.  In top left photo note slight radial arrangement of leaves near branch apex, compare with T. umbraculifera var. microcarpa.  In top right photo grayish scale scars appear at base of reddish orange branchlets; compare with T. wallichiana.  Illustration attached to specimen scanned separately and shown in lower photo;  the abaxial leaf margin is indicated to have 7 rows of smooth marginal cells followed by 5 rows of papillose cells and 12 rows of stomata; papillae on abaxial midrib cells are shown to be alternate; epidermal cells in x-section are shown to be elliptical and indicated to be 20 µm tall and 50 µm wide. Image to the right, Fig. 2 reproduced from Kwei & Hu (1974), showing abaxial leaf surface, midrib and stomata bands x65.

Hubei vicinity of Shibapan, 1850 m, Sino-Amer. 1980 Exped. 1824 (A). Illustration on packet in top photo scanned separately and shown in lower photo.  Center photo shows close-up of pointed seed and minute, broad-deltoid, yellowish green scales, and also grayish scale scars at base of branchlets. The abaxial leaf surface is indicated to have 8 rows of smooth marginal cells followed by no papillose cells and 12 rows of stomata; papillae on abaxial midrib cells are indicated to be medial; epidermal cells in x-section are shown to be elliptical, 20 µm tall and 37 µm wide.

Hubei: NE of Guanmenshan, Sino-Amer. 1980 Exped. 777 (A). Illustration on packet in top photo scanned separately and shown in lower photo.  Note minute, broadly deltoid, yellowish green scales at base of yellowish green branchlets in right photo.  Illustration indicates abaxial leaf surface has 7 rows of smooth marginal cells followed by 4 rows of papillose cells and 13 rows of stomata; papillae on abaxial midrib cells are shown to be alternate; epidermal cells in x-section are shown to be elliptical, and indicated to be 20 µm tall and 25 µm wide.

 

 

 

 

 

 

Yunnan: NE of Likiang Snow Range, Feng 630 (A). Photo attached to top photo scanned separately and shown in lower photo.  Note absence of scales at base of branchlets.  Photo is of abaxial midrib taken at 250x.  Papillae somewhat alternate in a single file on narrow epidermal cells.

 

Sichuan: Isotype, leaf x-section 250x, showing reddish elliptical epidermal cells.

 

 

 

 

 

 

 

 

 

China—Sichuan: E(O-)mei-hsien, Mt. Emei, Yu 869 (A).   Photo attached to specimen shows abaxial midrib cells taken at 400x; note marginal papillae and poorly differentiated stomata band from the midrib. Photo on upper right shows small grayish scales at base of some branchlets.  Illustration of leaf x-section shows rectangular epidermal cells, and abaxial 4 marginal cells without papillae and notes there are 12 stomata rows.  Stomata band shown in bottom photo.

 

Zhejiang: LiShui. LS001
Identification features applied:
Leaves relatively thick and short, recurved from base to apex, the younger ones more obtuse to apex than older leaves, not clasping the branchlet at base and not spreading in the same plane as the branchlet.  Taxus mairei, in contrast, has more sharply pointed leaves, the younger ones acuminate to acute at apex.

 

 

 

China—Sichuan:
E(O-)mei-hsien, Mt. Emei, Fang 18420 (A).  Photo attached to specimen shows part of stomata band and midrib, the midrib cells with marginal papillae. Illustration of leaf x-section shows rectangular epidermal cells indicated to be 12 µm tall and 25µm wide, and abaxial margin of 4 cells across without papillae and 8 papillose and 12–13 stomata rows. Palisade parenchyma cells are noted to be 100 µm long, each cell ~45 µm wide.

 

 

 

 

 

 

China—Sichuan: Kwang-yun Hsien, 1800 m; Wang 22602 (A). Right photo shows slightly larger cuspidate reddish brown scales at base of branchlets as often seen in T. wallichiana. Leaves often appear widest above the mid region while also slightly longer than usually seen for T. chinensis.  The phyllotaxy and leaf shape suggest T. chinensis. Illustration attached to specimen indicates leaf epidermal cells as seen in x-section are 25–30 µm- wide and 12–15 µm tall, midrib papillae are marginal and there are 12 stomata rows.

 

 

 

 

 

 

 

Guizhou: W side of the Fanjing Shan Mt. Range, 1100-1400 m, Sino Amer. Guizhou Bot. Exped. 1854 (GH). Photos attached to specimen scanned separately as shown at bottom, shows abaxial midrib, stomata band in part, and adjacent marginal cells.  Center photo shows minute scales at base of branchlets and close-up of seeds.  The illustration attached to specimen indicates a leaf has 14 marginal cells, medial papillae on accessory cells and marginal papillae on midrib.

 

 

 

 

The name T. chinensis was once used for any yew occurring naturally in China (Rehder 1940), and also Taiwan, Philippines, and Indonesia (Wilson 1926)—until the earlier legitimate names—that had been misclassified in Cephalotaxus and Tsuga—were applied; the code (Art. 11.4, 11.5) requires that the earliest epithet be adopted regardless of the genus it was erroneously assigned to—unless conserved. Rehder (1936), for example, discovered one—Tsuga mairei Lemée & Lév., but continued to use his name, T. chinensis, whereas Parlatore (1868) and Pilger (1903, 1916) had reported several earlier names (Cephalotaxus sumatrana, Cephalotaxus celebica) whose epithets were eventually adopted, T. celebica (Li 1963), T. sumatrana (de Laubenfels 1978); however, the correct name for a single subtropical species as applied by these authors would have to be T. wallichiana.

Not all yewologists accept just one species of Taxus in southern China (Table 1); Florin (1948a), for example, felt there were at least two: T. chinensis, which he treated as a variety of T. wallichiana with distribution primarily in Sichuan, and another that he considered a new species, T. speciosa, which was not entirely new since it had been earlier described—as already indicated, and Florin himself mentioned the names in synonymy (Cheng & Fu 1978). Florin’s two species were distinguished by the presence or absence of papillae on the abaxial leaf midrib, and var. chinensis was further distinguished from var. wallichiana (in the Himalayas) by the relatively shorter (oblong v. linear) leaves. He also indicated that T. baccata var. sinensis was synonymous with var. chinensis according to communications he had with Orr at Edinburgh who had sent him leaves of Henry’s collections (Henry 7155), which Henry himself had named var. sinensis. Although I have not studied the Edinburgh specimens of Henry’s collections, the type was selected based on material at E sent to Florin who cited Henry 7097, 7155.

Chinese botanists have since recognized up to four species and one variety of Taxus in China (Cheng & Fu 1978); however, they have misapplied and illegitimately combined previously known names. These included T. chinensis var. mairei (Lemée & Lév.) W. C. Cheng & L. K. Fu (illegit.), T. wallichiana (misapplied to T. contorta), and T. yunnanensis (superfluous for T. wallichiana). Hu (1964) followed Florin’s treatment (1948a) except she maintained T. chinensis as a species. Cheng & Fu (1978), however, reduced it again to a variety, but not according to ICBN as just indicated. Taxus chinensis and T. mairei were considered to differ only as varieties because the distinguishing feature—presence or absence of papillae on the leaf midrib (undersurface)—could not always be clearly decided due to the occurrence of intermediates (Kwei & Hu 1974; Cheng & Fu 1978), and also because the type for Cephalotaxus celebica Warb. had not been studied (Hu 1964; Cheng & Fu 1978). Hu (1964) concluded that the type for T. speciosa did not significantly differ from that of Taxus (Tsuga) mairei, whereas the type for Cephalotaxus celebica might differ because the only specimen she saw from the Celebes Islands (Neth. Ind. For. Serv. bb:19577, GH) had leaves with a papillose ventral (abaxial) midrib, and in her opinion this was distinct from the types of T. mairei and T. speciosa.

I have studied the same specimens that Hu studied at Harvard (annotated by Hu, July 1955), and largely concur with her identifications of T. chinensis (Hu 1964). Additionally, I have studied other specimens from Sulawesi, namely the type for Podocarpus (Taxus) celebicus Hemsley (K), Teyrmann 14190 (U), and a photocopy of a holotype fragment for Cephalotaxus (Taxus) celebica Warb. (S); these have similarly shaped leaves with a smooth midrib and broad marginal area of partially papillose cells on the abaxial surface; the “Neth. Ind For.” specimen (GH), in contrast, differs in having a papillose midrib as noted by Hu (1964). Based on Florin’s (1948a) account, and the similarity in leaf shape of the two type specimens—in which I have recognized T. sumatrana celebica by its long acuminate leaves (tapering from mid region; e.g., H. Smith 10401 [BM], Plate 6 in Florin, 1948a), I see no reason to disagree with Florin—that the Warburg type for T. celebica lacks papillae along the abaxial midrib; thus, while Cheng & Fu (1978) could have adopted this name in their revised treatment of Taxaceae in the Flora of China, the correct name under their species concept is T. sumatrana; the basionym was mentioned by Pilger (1903, Cephalotaxus sumatrana) who was cited by Cheng & Fu (1978). 

Currently, I distinguish T. chinensis by the pale yellowish green or “yellowish ochre” to “bronze” (“Prismacolor” chart) color on older branchlets (“dun colored”; Orr 1937), and by the relatively short (oblong), thick leaves, usually with conspicuous midrib papillae along epidermal cell walls. In making this distinction, I have independently reached the same conclusion as that by Pilger (1903, 1916), Orr (1937), Florin (1948a), and Hu (1964) for recognizing this taxon by its leaf and bud-scale characteristics, and also that by Orr (1937) for its branch color. Although branchlets of T. wallichiana vary in color from reddish orange to purplish, they lack this yellowish pigmentation, or are not yellowish green.

Taxus sumatrana and T. mairei also have similar bud-scales, and while they differ from T. chinensis in lacking papillae on the abaxial midrib and marginal cells—with rare exceptions, they show other differences. Their branchlets arise isodichotomously, often in a zigzag arrangement, compared to irregular, or anisodichotomous branching without a distinct pattern in T. chinensis, and their abaxial leaf surface has a truncated midrib, compared to a rounded (keel) midrib in T. chinensis.  Most specimens of T. chinensis can be distinguished from the Sumatrana Group in China by these features under a standard dissecting scope, but occasional specimens require microscopic examination of leaf sections to identify the distribution of papillae on the abaxial midrib and marginal regions as a confirmatory character trait. Confusion is mostly likely to occur with Taxus sp. (T. kingstonii Spjut ined.).

I also see T. chinensis as part of a species complex (Subgroup Chinensis, Spjut 2000) that is geographically and morphologically central with regard to the T. cuspidata alliance in northeastern temperate Asia, a Sumatrana Group centering in southeastern China, and a Wallichiana Subgroup in eastern Himalayas—as discussed to some extent earlier under T. wallichiana.  Leaves of T. chinensis frequently have a wider marginal region of cells without papillae on the abaxial surface—from 4–12 cells wide, occasionally angular epidermal cells as seen in x-sect. (from Guangxi, Sichuan, Yunnan, and Hubei), occasionally are linear in shape (W Hubei), and rarely are less papillose on the abaxial midrib cells (e.g., Hiep & Chan 405 from Vietnam, P). The marginal border of cells are usually thick-walled and trapezoidal in shape as seen in the T. cuspidata alliance, whereas specimens with longer leaves and/or angular shaped epidermal cells in transverse section are clearly related to T. wallichiana, or those with less papillae on midrib cells indicate closer ties to T. sumatrana.

The evolutionary relationship of T. chinensis to species of the T. cuspidata alliance is evident in the variation of the character traits they share.  They are differentiated from the Wallichiana Group by elliptically shaped epidermal cells in x-section (Spjut 1998a, 2000a,c).  Among those related to T. cuspidata are plants with a shrubby habit that have ascending to erect imbricate leaves—typified by T. caespitosa Nakai (e.g., Makino 43792 from Japan, S, topotype). Their similarity to T. chinensis is evident on the abaxial surface of leaves having a rounded keeled midrib (x-section) and a smooth marginal region of 8–12 trapezoidal cells, and by seeds being more sharply tapered to apex in contrast to those of T. sumatrana.  Taxus caespitosa varies more in development of papillae on the undersurface of leaves, especially on the midrib, whereas T. chinensis more often has a narrower marginal border of smooth cells, 4 cells wide.  This variation suggests a gradual differentiation of T. chinensis from T. wallichiana and T. caespitosa, which also has further differentiated itself by development of smaller seeds (shaped like a ‘Hershey Kiss’), by the conspicuous bubble like papillae along cell walls in T. chinensis appearing reduced to low concrescent ridges in T. caespitosa, and by loss of stomata.

Among the T. cuspidata alliance are plants with leaves arranged in nearly two-ranks (e.g., Wilson 10519, from South Korea, A BM GH US).  They appear more closely allied to T. sumatrana than to T. chinensis.  Their habit is typically a tree (T. biternata Spjut) in mixed conifer hardwood forests in northeastern temperate Asia (Kolesnikov 1935) with much divided branchlets as in T. mairei, which differs by a more isodichotomous arrangement, often in a distinct zigzag pattern (e.g., Fig. 11 in Liu 1960; Tsang 20694 from Guandong, China, A, US).  They also share with T. sumatrana the flattened to slightly rounded midrib as seen in x-section, a wider marginal region of epidermal cells without papillae—from 8–24 cells across, and a larger subglobose seed that differs by being angled near apex.   The differences between T. sumatrana and this T. cuspidata complex also appear clinal from southeastern China to southeastern Russia and Japan (Spjut 2000c, unpubl.). This may relate to paleoclimatic gradients in that region during the Pliocene and Pleistocene.  Thus, I recognize two lineages for the Cuspidata Alliance in eastern Asia.

A specimen of T. chinensis cited from Vietnam and others more frequently collected on Mt. Emei (Sichuan) were recognized in my annotations (A, GH) as being distinct for their “complanate” leaf arrangement.  This variant generally has a relatively wider abaxial leaf margin—from 7–12 cells across without papillae, and bears strong resemblance to T. baccata var. adpressa Hort. ex Carrière, which I consider a variety of T. canadensis (Spjut 2000b).  While it may have been derived from the T. chinensis/T. caespitosa complex, the similarity to European plants is remarkable in branching, leaf shape, and leaf anatomy (e.g., Summerhayes 2581 from near Kent, England, K), including a fossil from an Upper Miocene deposit (Kvaček 1986, “Taxus sp. 2”). The European plants seem to differ only by fewer stomata rows/band, and appear to intergrade with the European form of T. canadensis. Variety adpressa has also been thought to occur in Japan (Endlicher 1847), but it probably originated as a chance seedling of T. baccata in a nursery at Chester, England sometime around 1826 (Pilger 1916; Wilson 1916).  Nevertheless, plants near the border of Russia, China and North Korea that have relatively short obtuse leaves and distinct divaricate branching may prove to be equally related (e.g., Palezevski 88, BM, K) to both European and Asian morphs. Within this region, a distinct variety of yew has been recognized by its habit as a low flat-topped, rounded bush that spreads by layering, T. cuspidata var. microcarpa (Trautv.) Kolesnikov (1935). Its phyllotaxy, as might be measured by the frequency at which leaves develop along a branchlet, appears intermediate between T caespitosa and T. cuspidata.  One may speculate that the Manchurian shrub yew may have been derived from a former T. canadensis and T. sumatrana species alliance that occurred in eastern Asia, or perhaps from a T. canadensis clade that once stretched across Eurasia and eastern North America.

The Chinensis complex also extends into Indonesia and the Philippines where consistent morphological differences merit taxonomic distinction from T. chinensis.  I recognized one species (T. phytonii Spjut ined., type from Philippines, de Laubenfels P668, A) by the relatively flaccid (drooping) branches and leaves (Fig. 1 in de Laubenfels 1988), and by the leaves in herbarium specimens showing a sharp contrast in color between upper and lower surfaces—dark reddish (resinous) to blackish green above, and pale yellowish green to yellowish orange below on stomata bands, demarcated by narrow reddish midrib and marginal zones. The leaves along the abaxial marginal zone lack papillae across (2-) 4–6 (-8) epidermal cells that have relatively thin-walls and are slightly inflated.  The number of stomata rows/band has a narrower range—from (10-) 11–14 (-16) rows.  In leaf x-sections, the epidermal cells appear slightly inflated on the adaxial surface—with a distorted angular shape.  Several varieties were also recognized by differences in shape and size of axillary buds or bud-cones, and by differences in leaf color and arrangement. Affinities to T. wallichiana are seen in the linear-falcate acuminate leaves, nearly isodiametric epidermal cells on the adaxial leaf surface, the relatively narrow region of smooth marginal cells on the abaxial leaf surface, and in the slightly cuspidate bud-scales that persist at base of branchlets. Affinities to T. chinensis are seen in the yellowish tint on branchlets, loss of papillae on midrib cells—especially on the lower half of the abaxial leaf surface, and in cross sectional shapes of leaves. The majority of the specimens were collected in the Philippines, but rare specimens from Sulawesi (Neth. Ind. For. Serv. 20887, K), Taiwan (Wilson 11154, A), Yunnan (e.g., Tsai 59874, A) and northeastern India (Ludlow & Sherriff 3719, BM) are remarkably similar.

Other specimens show various combinations of the taxonomic features that I employ to differentiate T. wallichiana, T. chinensis and T. sumatrana.  They—occurring relatively infrequent among the collections—generally have turgid leaves with elliptically shaped epidermal cells in transverse-section, but vary in other aspects.  Included are specimens that could easily be referred to T. wallichiana  (e.g., Oliver from Ruby Mines in Myanmar at different elevations, three sheets, K), and others that appear more distinct but may be hybrids with T. sumatrana (e.g., Williams 1054 from Nepal, BM!), or T. chinensis as further discussed here.  An example of one species under study resembles T. wallichiana by shape, arrangement and color of leaves, and T. chinensis in branch color and lack of persistent bud-scales (e.g., Poilane 4150 and Schmid s.n. from South Vietnam, T. aff. chinensis in adnot., A, P; T. rehderiana Spjut ined. as shown elsewhere on this website). Another mentioned earlier under T. wallichiana from Mt. Emei has these character features reversed  (T. scutata Spjut ined., e.g., Tsai 58464 from Yunnan, A, P; Sino-Amer. 1980 Exped. 585 from W Hubei, GH; Hu 8619 from W Sichuan, A).  A third taxon under study is identified by the leaves showing less contrast in color between upper and lower surfaces with further differences in leaves being rigid (e.g., Neth. Ind For. bb:19577 from Sulawesi, GH; C-j. Chang s.n., from Hualien, Taiwan, wba [private herb.]) or flaccid  (e.g., de Laubenfels 669, 670 A and C-j Chang s.n. from Taiwan, wba).

Several specimens from Sichuan and Zhejiang are included under T. chinensis despite their deviation in a number of features (Chiao & Fan 464, A, P, US; Ching 1676, A, P, US; Chens s.n. & locality, P).  They show strong similarity to T mairei in branching, leaf arrangement, leaf shape (in length and in x-section), and in the strongly compressed epidermal cells; however, I gave more weight to the conspicuous papillae positioned marginally on the abaxial midrib epidermal cells, and to a relatively narrow marginal zone of cells without papillae–from 7–10 cells across. I considered these features taxonomically significant based on their apparent ancestral relationships.  This morph is similar to the extinct T. engelhardtii Kvaček (1986) that was described from a late Oligocene deposit in Europe except that T. engelhardtii has more widely spaced stomata in fewer rows (7–10 rows fide Kvaček), although this type of stomata band appears evident in an extant species in Sichuan and Yunnan (T. florinii Spjut ined).

CONCLUSION

Taxus chinensis, T. contorta, T. wallichiana and related species are believed to have evolved in eco-geographically distinct regions that had remained relatively stable over a long period of time during the Tertiary, most likely during the Paleocene and Eocene.  The increasing aridity and cooler climate during the Neogene (Axelrod 1975) may have led to fragmentation of former clinal patterns of branching and leaf characteristics of Taxus as seen today between temperate and subtropical species complexes in Asia. Taxus chinensis occupies a central position to these various, poorly understood complexes. 

It should be noted that species of vascular plants have been recognized in Tertiary deposits to occur more widely across oceanic barriers that now exist  (Manchester 1999). Many examples are comparable to the distribution of extant species of Taxus (e.g., T. canadensis; Spjut submitted).  This may help explain why Pilger’s (1903) subspecies of Taxus, which have generally been accepted as species, appear to defy morphological classification, and have not received support from molecular data, except for North American species. Their extant distribution patterns are also comparable to bryophytes in which their longevity, survival by vegetative reproduction, and variable leaf anatomy, indicate a slow rate of evolution (Schofield & Crum 1972).

Since there is a lack of evidence for reproductive isolating characters in Taxus—other than eco-geographical isolation, hybridization might be expected where species populations are sympatric. Taxus chinensis possibly evolved from a hybrid complex between the Cuspidata alliance and the Wallichiana Group (see Spjut 2007a). Also, the oscillating climate changes during the Pleistocene may have led to frequent genetic exchange between formerly isolated populations of Taxus that resulted in the various leaf anatomical combinations of features that are evident in Asian Taxus.  Leaf anatomical characters are also show the greatest variation in Asia (Spjut 2007a).

Assuming that both Tertiary intermediates and Pleistocene hybrids survive—with little change in their morphology, differentiating between such entities may be more of academic interest than of taxonomic value. Arriving at a reasonable taxonomic solution requires sifting out the most common or distinct morphological pattern characteristics.  Molecular analyses may eventually demonstrate the complexity of the problem, but for traditional species classification purposes, morphological characteristics of taxonomic value are required in order to draw comparisons to type specimens. And while molecular data might aid in elucidating phylogenetic relationships, I believe such data must be guided by morphological criteria, not by geographical criteria alone—because it is becoming increasingly evident that species of Taxus in Asia have evolved more in response to ecological differences than to geographical isolation.

Finally, the taxonomic complexity in the genus suggests that species and varieties may need to be distinguished by a suite of morphological features for which no single character can be relied upon entirely.  Rare variants then have to be evaluated on the basis of uniqueness and whether there is evidence for an evolutionary basis as seen from a study over the entire range of the genus.

ACKNOWLEDGMENTS

I thank Drs. Roy Vickery and Charlie Jarvis for making specimens and rare books available at BM, providing photocopies of literature, and allowing specimens to be photographed; Dr. Ph. Morat at P for making available their specimens, and allowing them to be photographed; Dr. Arne Anderberg at S for his communications, hardcopies from their online database of Taxus specimens, and loan to US; Dr. Zi-yu Cao at PE for photocopies and leaves of “isotype” of T. yunnanensis, and correspondence; Dr. Umberto Mossetti at BOLO for providing leaves of their type of T. orientalis, and its illustration by Bertoloni; Dr. Patricia Holmgren for providing photocopies of their types of T. wallichiana, and Dr. Alfred Schuyler for allowing me to study of specimens at PH; similarly, I am grateful for the assistance from Peter Edwards at K during my visit; Peter Mazzeo (retired) at NA for obtaining loans from A, BH, BM, GH, K, M, and U, George Russell and Katherine Rankin at US for obtaining and maintaining loans from S, and for study of their collections; and curators at E who have provided a loan of original material of T. lindleyana.

Thanks also to Dr. Dan Nicolson for helpful discussions on nomenclatural matters and review comments of the manuscript; to Dr. John Thieret for his twice generous editorial review and comments, to the National Agricultural Library for assistance in obtaining rare journals; the Library of Congress in Washington, D.C.; to the USDA Pacific Northwest Research Station and USDA Forest Service in that region for providing fresh material of T. brevifolia and for field assistance; Kenneth Cochran at the Secrest Arboretum for field assistance and providing specimens; and to John Wiersema at the USDA Systematic Botany Laboratory in Beltsville for discussions on nomenclature in the early stages of this paper.

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Table 1
Footnote: Peer Reviewed for publication in Sida (2001).   Note: an edited version of this manuscript was resubmitted for peer review in May 2006. Incorporated into a larger manuscript that has completed peer review in Dec. 2006 and finally published August 2007.

Presented on the Web: April 2003;  Photos of specimens added May 13-19, and July 22, 2006 Also added: Links to table on leaf anatomical data and to an explanation for the characters May 2006; Taxus fuana reduced to synonomy based on study of its type, Jan. 2007. Range of var. wallichiana was extended to SE Tibet based on specimen received 24 Apr 2007.

Additional Footnote (June 2010): First submitted to Taxon in 1998. The manuscript was not considered.  Members of the IAPT who serve on the nomenclatural committee have continued to support the use the illegitimate names of Taxus and to justify other names of Taxus without taxonomic merit.  A good example is the MBG and USDA who have gone to extreme measures to justify use of T. fuana by recognizing T. contorta being found only in Afghanistan.  Earlier Farjon had tried to justify T. fuana by recognizing  as endemic to the type locality in Tibet. The author of this website does not support such nonsense and has discontinued his membership in the IAPT as a result. Also, this website has been attacked by hackers who  have deleted images and references to images, which have had to be restored on number of occasions from back-up files.