Ceanothus. Pernnials, shrubs or small trees, leaves persisting for more than season, or seasonally deciduous, simple, alternate or opposite, often in clusters; flowers white, blue, purple, lavender, or pink, individually small, <5mm, conspicuous by their numbers in fascicles on pedicels spreading in an umbrella-like fashion, or shortly dichotomously branched, from a common area along short to elongated floral scapes, arising terminally on short leafy or leafless spur shoots or peduncles; sepals and petals 5, similar in color, arising from the rim of an urn-shaped hypanthium within which is a 3-lobed ovary surrounded by a fleshy resinous disk; sepals united at base (calyx) with the hypanthium, lobes triangular or elliptic; petals basally clawed, terminally hood-like; stamens 5, opposite the petals; gynoecium schizocarpic, styles partly united, 3-cleft; young fruit often with finger-like appendages arising from the hypanthium or from the disk, pericarp often with warts or horns that enlarge or shrink as the pericarpium matures, at maturity carpels separate and open along their ventral sutures and partly along dorsal sutures (coccarium), preceded by separation of inner pericarp layer, explosively breaking from the disk, leaving behind half of an empty 3-partioned cup; seeds one per carpel; ± 60 spp., 45 in California, 10 or 11 in Kern County. Many species in horticulture are drought tolerant hybrids (Fross & Wilken 2006).

     Moerman reported medicinal uses for eight species of Ceanothus by native Americans—C. americanus Linnaeus 1753 by the Alabama, Chippewa, Iroquois, Menominee, and Meswaki for treating injured legs, rheumatism, gastrointestinal problems, pulmonary problems, diarrhea, colds, vemereal disease, diabetes, snakebite, constipation and bloating; leaves of C. fendleri A. Gray 1849 used by the Navajo (Kayenta, Ramah) for sore mounth, and with twigs as an emetic, Chippewa used root of  C. herbaceous Rafinesque 1808 as a cough remedy, Karok used plant of C. integerrimus for injury in giving birth; leaves and fruits of C. leucodermis used by Digueño for itch, poison oak, sores; Okanagan-Coville applied powered bark of C. sanguineus Pursh 1814 to burns, the Sanpoil applied sapwood with grease or oil to wounds or sores; twigs-leaves of C. thyrsiflorus Eschscholtz 1826 used by Poliklah to wash newborn babies; leaves of C. velutinus Douglas 1831 used by Great Basin Indian, Karok, Modesse, Okanagan-Coville, Warm Springs (Oregon Indian), and by the Thompson for cough, washing and powedering babies, as a deodorant, and for fevers, dandruff; stems also used by Thompson for rheumatism, or with leaves for arthritis, weight loss, and for cancer. In Boy Scout training, I learned to use flowers as a substitute for hand soap.

     The National Cancer Institute (NCI) screened 120 extracts of Ceanothus samples prior to 1980, only one was active, an aqueous ethanol extract of C. americanus root in the SA bioassay (Jan 1966, CPAM 1976). The active agent(s) unknown but probably a saponin, which would have been of little interest for cancer chemotherapy. Despite the widespread use of Ceanothus by native Americans, relatively few publications in Pub Med mention biologically active agents, which might be expected in view of the lack of antitumor activity in the NCI antitumor screeing program. It may be noted that the Morton Arboretum (PI William Hess) collected 42 samples for the NCI during 1996–2000 from nine species, generally consisting of root, stem, and/or twig-leaves combined, and that the WBA (PI Richard Spjut) obtained another 35 samples from 11 species during 2001–2003, seven of which were root-bark and stem-bark—parts most likely to contain active chemicals; additionally, the WBA collected five more samples from two additional species during 2007–2008 for the NCI. 

     Nitrogen-fixing bacteria, namely Frankia, form symbiotic (actinorrhizal) nodular associations with Ceanothus. Among eight species studied in California—that included samples along elevation gradients in the southern Sierra Nevada—relationships appeared geographical with Frankia strains (Oakely et al. 2004).  However, in a related genus, Colubrina, actinosynnemal associations show taxonomic relationships in which two closely related species (C. californica, C. texensis) were found to have highly significant antitumor activity; colubrinol, a maytansinoid compound. generally found in actinomycetes, was isolated. Within rhe Rosid Clade (APG III) related genera in Celastraceae were found to have ansimitocins (maytansinoids); they were isolated from Gymnosporia in India, Ethiopia, Kenya, and Putterlickia in South Africa. During the mid 1970’s, Robert Perdue of the Agricultural Research Service, and John Douros, Chief of the Natural Products Branch in the NCI, collected fresh plant and soil from active species sites in Africa and Texas in an effort to identify and isolate the microbe(s); they were unsuccessful, however. Strong circumstantial evidence for an actinosynnemal association has since been found to exist in the rhizophere of P. verrucosa (Wings et al. 2013). 

.     Two subgenera are generally distinguished by persistent vs. deciduous stipules, and by the leaf arrangement of opposite vs. alternate, and by whether or not leaf margins are glandular.  Persistent knobby stipules characterize subgenus Cerastes; the stipules generally conical in shape or horn-like in contrast to deciduous scaly stipules in subgenus Ceanothus; however, in Kern County, stipules in the Cerastes species of C. cuneatus and C. cf. vestitus are not persistent except perhaps as scar tissue. Nevertheless, the size and degree to which stipules persist in species of subgenus Cerastes are given weight in the key that follows to differentiate the Kern County species from those in Arizona and Mexico.  Fross and Wilken (2006) noted that in the central region of Mexico, species with conspicuous stipules, such as C. pauciflorus, which occur at scattered mountainous locations, have intermediates in northern Mexico; similarily. intermediates are evident between C. vestitus (isotype from Tehachapi Mts.) and Ceanothus cf. vestitus on Mount Pinos. Fruit characteristics, in which the fruit itself varies in development, appear to have taxonomic value; more study needed of fruit development. 

Key to Species of Ceanothus in Kern County

1. Branches and leaves opposite (subgenus Cerastes).......................................... 2

1. Branches and leaves alternate (subgenus Ceanothus)..................................... 9

2. Stipules on older leafy twigs inconspicuous (< petiole length and
        thickness), vestigial, or not evident............................................................. 3

2. Stipules conspicuous on leafy twigs, > 2mm long, shaped much like
        a chocolate ‘Hershey Kiss, often persistent on older leafless twigs............. 5

3.  Leaf blades ± round although more tapered to petiole, margins
       thickened or slightly recurved, undulate with 5–7 regularly
       spaced and equally developed teeth along each side; leaf
       undersurface with sharply defined venation, the tertiary reticulate
       veins slightly raised, white areolate; stipules conical, like an orange
       gummy, rugose with age; fruit horns short, mostly in mid region of
      carpel, spike-like; “borders of the pine forest near
      Tehachapi”                     ........... ........... ........... ................. Ceanothus vestitus

3. Leaf blades ± wedge shaped although sometimes round when young,
       margins entire; leaf undersurface venation obscure or prominent
       with thick raised or flush veins, white areolate or not; stipules in
       Kern County plants rarely evident, blackened lens-like leaf scars
       often more conspicuous; fruit horns variable, usually well
       developed and wart-like (except cf. vestitus)................................................ 4

4. Undersurface of leaves with prominent reticulate venation, or veins
       obscured entirely by hairs; immature fruits resinous shriveled (like bubble
       wrap), sometimes lobed, and usually with thick warty horns that are erect
       to spreading; common in mixed pine-oak woodlands and margins
       of adjacent montane chaparral in Kern County............. Ceanothus cuneatus

4. Undersurface of leaves with white flecks (hair patches, stomata crypts)
       aligned along mid and lateral veins; fruit shiny red, smooth, or with
       short projections appearing like pimples, spikes, or flattened
       warts at right angles near base; mostly montane chaparral on western
       and northern slopes above ghost pine-oak and juniper woodlands in the
       Piute Mts. region, in pinyon pine woodlands with manzanita and/or
       juniper on east and southern slopes bordering the Mojave Desert, and
       in montane chaparral on northern slopes in the Transverse Ranges and
       in evergreen oak and juniper woodlands along the eastern
      Sierra Nevada                ........... ........... ........... ........... Ceanothus cf. vestitus

4. Leaf venation or hair patches not clearly evident on undersurface,
       ± uniformly downy pubescent (leaves usually narrowly elliptical,
       similar to C.  pauciflorus except for the inconspicuous stipules);
       woodlands in Kern River Canyon and upper montane chaparral in
       the Piute Mts and Sierra Nevada................................ Ceanothus × cuneatus

5.  Persistent stipules long conical—like goat horns, ± twice the length of
       petiole, 3× longer than wide; mainland Mexico.......... Ceanothus pauciflorus

5.  Persistent stipules short conical to mound-like, ± as long as petiole............... 6

6.  Leaves wedge-shaped to elliptic, >1.5× longer than wide, thickened
      lip-like along margins; leaf undersurface areolate reticulate, similar to
      C. cuneatus except for the incomplete tertiary vein connections;
      southwestern desert mountains but not Californa.............. Ceanothus greggii

6.  Leaves broad elliptic to ± round in outline, 1–1.5× longer than wide,
       toothed and/or tightly revolute along margins; leaf undersurface
       with prominent pinnate venation......... ........... ............................................. 7

7.  Low shrubs broader than high, mound to mat-like....... Ceanothus pinetorum

7.  Medium to large shrubs, usually taller than wide............................................ 8

8.  Leaves plane to upcurved, toothed, slightly contorted along margins,
         truncated and/or with a terminal broad triangular tooth tapering to
         a sharply pointed apex; stipules conspicuous on twigs after leaves
         have fallen, longer than wide, often aging black, cone-like tip
         ± curved and pointed  .............................................. Ceanothus perplexans

8. Leaves wrinkled when dried, plain or tightly curled (revolute) along
wavy toothed margins to below mid region, ± white underneath,
reticulate veins ± obscured by white hairs (var. crassifolius), or
white areolate (var. planus); stipules not usually persistent on leafless
portions of twigs, nearly round to short conical, often wider than high,
remainng red orange, cone-like tip ± straight, with a blunt or rounded
tip                                ....................... ........... .......... Ceanothus crassifolius

9. Spiny                               ............................................................................... 10

9. Not spiny                         ............................................................................... 11

10. Shrubs wider than tall, <1.5 m high, conifer forest
       region                            ............................................... Ceanothus cordulatus

10. Shrubs taller than wide, often 2–4 m high; foothill and montane
      woodlands                     ............................................. Ceanothus leucodermis

11. Leaves evergreen with glandular teeth along margins................................. 12

11. Leaves deciduous or semi-deciduous, margins entire or denticulate
      at apex                           ............................................................................... 14

12. Erect shrubs; leaves 3-veined at base........................... Ceanothus oliganthus

12. Low round or matted shrubs; leaves pinnately veined from base................ 13

13. Growing as mats not more than 30 cm high; draws, flats, oak |
       pine wd or forest, 900–1800 m, Klamath, Cascades, Sierra Nevada;
       May–Jun                       ............................................ Ceanothus diversifolius

13. Plants not as low to the ground, 30–80 cm high; open wooded slopes
       and road banks of ponderosa pine cedar fir and Doug fir forests,
      1200–3500 ft, N. Coast Ranges; Klamath Mts; foothills of Cascade
      Range & Sierra Nevada, Apr–May................................. Ceanothus lemmonii

14. Leaf blades oval in outline, tapering from near base, 2.5–7 cm
      long; lateral veins 3–4 pairs, 3-veined at base; petioles
      6–12 mm long                ............................................ Ceanothus integerrimus

14. Leaf blades partly elliptic, the  margins ± parallel in mid region
      before tapering to apex, 0.6–3.5 cm long; lateral veins 6 pairs,
      not 3-veined except seedlings and stump sprouts;
      petioles 2–5 mm long    ................................................... Ceanothus palmeri

Ceanothus cordulatus Kellogg 1861. Mountain white thorn, Snow bush.  Low intricately  branched shrub with many short zigzag spiny branches along main stems, wider than tall with a broad flat crown, to 50 cm high and several m or more broad; bark whitish-gray; branches alternate, ending in sharp spines; leaves alternate, thin, 3-veined at base, round or broad elliptical, 1–2× longer than wide, 1–2.5 cm long, slightly folded or curved upwards along the midrib, entire or nearly so; flowers May–Jul, white, fragrant, on long pedicels1.5–3 cm in umbellate fascicles arising from short thorny branches with or without leaves; fruit Jul–Aug. Montane conifer forest above 4,000 ft; southern Oregon to the San Pedro Mártir in Baja California except South Coast Ranges, and to the Spring Mts. in southwestern Nevada.  Type from near Washoe, NV. “Mountain white thorn chaparral” (alliance) recognized in MCV2 when >50% relative cover in the shrub canopy. Kern Co.: “Common in the high mountains, mostly in exposed rocky places, often around rugged summits” (Twisselmann), 1768–2535 m (CCH).

Ceanothus crassifolius Torrey 1857.  Hoary ceanothus. Shrub, stiff and openly branched throughout, 1–4 m high; branches opposite, gray or reddish brown 1^st yr, not spine tipped; leaves opposite, decussate, not clustered, on short thick petioles 2–5 mm long, blades broadly elliptic or wider above the mid region, or with almost parallel margins, 1–2× longer than wide, 0.5–3.0 cm long, slightly convex across upper (adaxial) surface, usually markedly different in color on both surfaces, shiny green to yellow green above, whitish hairy below(var. crassifolius) , or whitish areolate (var. planus); margins distinctively toothed, undulate and shortly curled under; persistent stipules similar to a ‘Hershey Kiss’, usually shorter than length of petiole, as thick or thicker than petiole at base, 2–3 mm thick, remaining orange with age; flowers Jan–Apr, white, with dark disk on pedicels 7–10 mm in umbel-like fascicles at ends of shorter floral shoots 1–5 mm from short lateral branches; fruit 7–8 mm wide, with erect lobe-like basal appendages in early development, appearing 6-lobed, 3-lobed at maturity with “horns” up to 2 mm. Common below 4,000 ft in chaparral of South Coast Ranges, Transverse Ranges, Peninsular Ranges south to northwestern Baja California. Type from “Mountains south of Los Angeles,” “Canon Pass” (NYBG 00406521, lectotype, Burge et al. Dec. 2015) or “Cojon Pass” (NYBG 406520), probably Cajon Pass, Bigelow. “Hoary leaf ceanothus chaparral” (alliance) recognized when “>60% relative cover in the shrub canopy,” or when in association with Adenostoma fasciculatum with not less cover (MCV2).  Kern Co: CCH: Tehachapi Mountains, H . Bauer, 1 Apr 1928 (POM285186); near Keene, 30 Apr 1928 (RSA398569), identified var. planus Abrams 1910 (type from Ventura Co., Topatopa Mts., Red Reef Canyon, holotype DS!)

           Ceanothus crassifolius generally seems to have two leaf forms as seen from review of images collected outside Kern County, one has uniformly densely white hairy leaves on the undersurface to the extent that the tertiary veins are not discernible, represented by the lectotype); the other has a white areolate undersurface with prominent reticulate venation, which corresponds to the holotype (DS) for var. planus. Variety planus is similar to the type of C. vestitus in the thickened and toothed leaf margins, but differs in the larger persistent stipules and white areolate leaf undersurface, which is much like C. cuenatus.  The specimens collected near Keene may prove to be additional records for C. vestitus in Kern County.

Ceanothus cuneatus (Rhamnus cuneata Hooker 1831) Nuttall 1838 (holotype K!). Buck brush  Medium to large shrubs, 1–3 m high (can be prostrate outside Kern Co); branches opposite, numerous, short, stiff, intertwined, not ending in spines, whitish gray; leaves persistent for more than one season, opposite, thick, widest near the apex, narrowest near the base (cuneate), 1–2× longer than wide, entire or rarely with marginal teeth, folded upwards along the midrib or the upper (adaxial) surface appearing concave (“cupped”), undersurface of leaves bald to uniformly hairy, veins conspicuous, the lateral veins arcuate-pinnate, thick, ± two patterns: (1) secondary laterals forming predominantly towards the margin or (2) secondary laterals typically (holotype) branching equally towards midrib and margin; tertiary veins reticulate in several divisions between laterals, white areolate (between the veins) in #1, or sometimes not white in #2, not all connected, the ultimate incomplete, stipules relatively small, triangular or conical, shorter and narrower than petiole, usually < 1 mm long, dark brown to black, scarcely persistent with older leaves, not easily distinguished from old leaf scars after leaves shed; flowers Feb–May, white (in Kern Co.), on pedicels about the length of leaves, clustered along a short thick floral axis extending from a short woody shoot near ends of short branches; immature fruit three-lobed with erect wart-like horns, or in some plants, which may represent a distinct variety (C. cf. cuneatus), immature fruit with appendages larger than the ovary lobes, shrinking at maturity.  A common shrub in California shrublands outside desert regions over a wide range in elevation, to San Pedro Mártir, Baja California. Type from Oregon, “abundant near the sources of the Multonomak [Willamette] River, in sandy soils growing under the shade of Pinus lambertiana.” Buckbrush chaparral (alliance) recognized in MCV2 when >60% relative cover in the shrub canopy. Kern Co: Primarily Sierra Nevada Region west of Walker Pass, oak-pine woodlands and chaparral, 441–1829 m (CCH).

            Fross and Wilken (2006) indicated that Rhamnus cuneata described by Hooker was not a basionym, because they  concluded from comments in Torrey and Gray (1838) that the type collected by Douglas probably belonged to another species or variety (in another genus). A character feature questioned was the “ferrugineous” color of the branches and/or hairs (Brandegee 1894). However, a holotype evident at Kew (K), a specimen near an imprinted stamp “Herbarium Hookerianum,” has the ferrugineous color (Spjut Sep 2015). It also has flowers in bud as was originally described, and is accompanied by a handwritten label signed by Douglas titled “Rhamnus,” below stating where he collected it (at the type locality detailed above).  It clearly belongs to C. cuneatus as also described by Nuttall, evident by the persistent stipules (subgenus Cerastes) and wedge shaped opposite leaves with a white reticulate undersurface. The ferrugineous color on the branches and leaves may be a product of drying the specimen in a more humid climate. Furthermore, Nuttall adopted the epithet cuneatus from Hooker (1831). The correct citation, therefore, is Ceanothus cuneatus (Hooker 1831) Nuttall 1838, not “C. cuneatus Nutt.” as concluded by Fross and Wilken (2006) and Wilken (JM2). The specimen as since been designated lectotype (Burge et al. Dec 2015).  Plants in Kern County have smaller less persistent stipules, possibly as a result of past hybridization and introgression with C. cf. vestitus; see Fross and Wilken (2006).  These species have been distinguished by whether the upper leaf surface is concave (“cupped”) or flat (e.g., Fross & Wilken 2006; Stuart & Sawyer 2001; Munz 1959; McMinn 1939); however, I recognize both species to have cupped leaves.

 “Fruit horns” (warts) in Kern County plants of Ceanothus cuneatus seem to vary in position and development.  The fruit warts initially appear to curve upwads from near the rim of the hypanthium or near base of ovary. As the fruit enlarges, the warts appear more medial in position and spread outwards rather than upwards. The medial position of the warts is generally associated with the fruit of  C. cf. vestitus, but fruit “horns” in C. cf. vestitus—when developed—appear more like pimples or spikes rather than warts as also seen in C. perplexans (McMinn 1939 illus.).  Among the various illustrations, one in Abrams and Ferris (1951) most accurately depicts C. cuneatus in Kern County.   

Ceanothus diversifolius Kellogg 1855. Pine mat. Low evergreen shrub; stems creeping along ground, rooting along the way; branches not stiff but flexible, not spiny, leaves alternate, thin, darker green above than below, elliptical or wider above the mid region, tapering at both ends, 2–2.5× longer than wide, minutely toothed along thin margins, especially in the upper half, pinnately veined, 3–5 lateral veins, the basal connecting to  mid vein at base (appearing 3 veined); flowers Apr–Jun, blue or purplish blue, on pedicels 5–11 mm in small fascicles clustered near end of a floral axis (peducle) extending shortly beyond the leaves, all appearing in hemispherical or short cylindrical masses; fruit crested near top.  Occasional in draws and flats in oak-conifer forests from 3,000 to 6,000 ft , from Shasta and Siskiyou cos. south mainly along the Sierra Nevada to Kern Co. Type from El Dorado  Co. between Emerald Bay and Cascade Lake. Kern Co.: “Scarce in and just below the ponderosa pine forest on the west slope of the Greenhorn Range south to Cedar Creek” (Twisselmann), 1,423–1,829 m (CCH); also observed on east slope of Greenhorn Range along Sawmill Road.

Ceanothus greggii A. Gray 1853. Gregg’s ceanothus. Intricately branched shrub to 1.8 m; branches rigid, opposite, gray; stipules short conical, ± as thick as petiole, 1 mm diam at base, aging dark brown to black, persistent after leaves shed; leaves persisting more than one season, opposite, in fascicles of several or more, leathery, ± wedge-shaped to narrowly elliptical, usually widest above mid  region, more narrowly tapered to base than to apex, plane to convex across top surface, or cupped, 5–16 mm long; leaf margins thickened, lip-like, slightly revolute in mid region, entire or with 1 or 2 teeth near base, or more toothed above; upper (adaxial) surface dark or pale green; leaf undersurface paler green or densely white short hairy, the  veins all relatively thick,  not as finely reticulate between lateral veins compared to C. cuneatus, the tertiary veins not always complete, areoles ± angular, white to green; flowers Apr–Jun, white, clustered on a short peduncle. Fruit mostly smooth, without horns. Mexico, southwestern Texas, New Mexico, Arizona. Type from Mexico, Coahuila, Battlefield of Buenavista, near Saltillo. Not in Kern County.  Specimen images. Arizona. Yavapai Co.:  Agua Fria Natl. Mon., desert scrub-grassland rocky slope, 3136 ft, Hodgson, 2 May 2003 (DES). SEINet. Maricopa Co: various thorny deciduous shrubs and cacti noted with Larrea and Juniperus, 2100 ft, Goldman & Ward, 7 Feb 2005 (DES).  Coconino Co.: 2/3 way down Schnebly Hill, 34.88194  -111.67556, C.L. Schmidt, 04 Jul 1940 (ARIZ).  Gila Co.:  Fossil Creek Rd, pinyon-juniper-scrub oak community, 3831 ft, Hodgson et al., 31 Mar 2012 (DES).

            Plants referred to as Ceanothus cf. vestitus differ by the orange hummy-like stipules with a papillose surface, in contrast to C. greggii stipules appearing dark brown with a relatively smooth surface. Ceanothus cf. vestitus  also differs by the leaves not having a lip-like margin, and by the undersurface having white flecks (patches of hairs) aligned along the lateral and mid veins, based on comparison  of Kern County plants to type specimens of C. greggii, including the lectotype at the Harvard University Herbaria (HUH)—GH.

Ceanothus integerrimus Hooker & Arnott 1839-40 var. macrothyrsus (C. thyrsiflorus Eschscholtz 1826 var. macrothyrsus Torrey 1874) G.T. Benson 1930 [Includes C. integerrimus var. californicus (C. californicus Kellogg 1855) G. T. Benson 1930; C. integerrimus var. puberulus (C. puberulus Greene 1904 ) Abrams1910]. Deer brush.  Deciduous thorn-less shrub with erect branching stems, the branches usually more above the mid region of the plant than below, forming a hemispherical crown, to 2 m or more high; leaves alternate, elliptical to widest below the mid region, pinnately veined with 3–4 lateral pairs, 3-veined at base, margins not conspicuously toothed; flowering May–Jun; flowers in large dense pyramidal clusters (panicles) above the leafy portion of the plant, white to pink or blue, the color variation often seen in the same population, fruit often laterally crested.  Common in much of California, especially in mixed evergreen and ponderosa to Jeffrey pine forests, to Washington and Arizona.  Type from “Banks of Umqua, Oregon.”  Deer brush chaparral recognized in MCV2 when >50% relative cover in shrub canopy.  Kern Co.: “Scarce in a dense growth of shrubby canyon live oaks near the summit of Tejon Canyon, rare on a bank in the ponderosa pine forest just south of Greenhorn Pass,” “occasional in the Jeffrey pine forest in the Mt. Pinos region” (Twisselmann), 904–2,073 m (CCH). Occasionally observed on road banks along Rancheria road, forest roads on Breckenridge Mt. Rd in ponderosa pine forest, and locally frequent on Cerro Noroeste (Mt. Abel).  Infusion of bark used as a tonic (Krochmal et al. 1954).

Ceanothus lemmonii C. Parry. 1889. Lemmon's ceanothus.  Compact, densely branched evergreen shrub, 0.5 to 1 m high and broad; branches gray aging glaucous, leaves alternate, elliptic to shortly parallel along margins, inconspicuously 1 or 3-veined from base, plicate, 1.2–3.3 cm long; denticulate to serrulata along margins; stipules thin, deciduous; flower Apr–May, in subumbellate clusters. One record in CCH reported from the Greenhorn Range, Cedar Creek Camp above Glennville, 1311 m (L. Benson, 22 May 1951, annotated by D. Charlton in 1987, CCH), probably C. diversifolius.  Ceanothus lemmonii is a northern Sierra Nevada species extending into the Klamath and Cascade regions, the nearest Sierra Nevada record to Kern Co. is in Tuolumne Co., 1.5 miles north of Sonora at 2,900 ft.  Type from Johnson’s Ranch near Quincy, Placer Co., CA.

            Although the referenced specimen above from near Cedar Creek Camp in Kern Co. may be C. diversifolius, the vegetation in the area has been extensively grazed (pers. obs. Oct 2013). Rhamnus ilicifolia, for example, was observed as a densely compact and intricately branched low, broad, flat-topped shrub. Cattle observed grazing in the area undoubtedly contributed to the stunted growth of shrubs, which in turn made it difficult to recognize R. ilicifolia as different from that of the coastal R. crocea, while its habit could also be easily mistaken for C. lemmonii.

Ceanothus leucodermis Greene 1895. Chaparral white thorn. Erect evergreen multistemmed shrub with long recurved branches bearing many short zigzag spine-tipped branchlets, to 3 m or more high and 1–2 m broad; older plants often with one or more definite upright trunks; bark whitish-gray to brown; branches alternate, pale gray or pale green, smooth, glaucous at maturity; leaves alternate, pale whitish green (somewhat glaucous when young), or shiny green, broad elliptical to heart-shaped,. 1–2.5× longer than wide, 1–3 cm long, 3-veined from base, entire to shallowly toothed along margins; flowers Apr–Jun, white to blue in terminal scapes on pedicels 4–9 mm, scapes with a primary axis, often branched at base, the whole inflorescence pyramidal to cylindrical in outline, the pedicelled flowers arising singles or in umbellate fascicles, in fruiting inflorescence appearing like a cluster of grapes; fruit yellow green, sticky, truncated at top, not crested. Woodlands and chaparral below 7,000 ft in the Central and Southern Coast Ranges to the Peninsular Ranges and along the western Sierra Nevada bordering the Valley to the San Pedro Mártir in Baja California.  Type from California without specific locations.  White thorn chaparral recognized in MCV2 when >60% relative cover in shrub canopy.  Kern Co.: Frequent in Kern Canyon, of scattered occurrences in the mountains, Sierra Nevada Region and Tehachapi Mts., 610–2,200 m.  Plants with toothed leaf margins occur  frequently. In Kern Canyon those with leaves mostly green undersurface resemble C. cyaneus Eastwood 1927.

Ceanothus oliganthus Nuttall 1838. Hairy ceanothus. Shrub, twigs round, leaves alternate, minutely and closely denticulate along margins, hairy along veins underneath; flowers in on terminal elongated scapes with short lateral branches of fascicled flowers. Sierra Nevada; Tehachapi Mountains region Highway 99. Caliente Creek Drainage area, 1133 m. (Ramsey & Ramsey, 23 May 1937, CCH).  It was annotated by “P.W.” in 1965.  The species occurs mainly along the Outer Coast, Transverse Ranges and Peninsular Ranges.  It is very similar to C. integerrimus, which differs by its teeth along the leaf margins not being glandular thickened.

Ceanothus palmeri Trelease 1888. Palmer’s Ceanothus. Shrub to 3 m; bark gray green, branches alternate, stipule scale-like; leaves alternate, partly deciduous, long elliptic or with parallel margins, 3–4× longer than wide, (0.6-) 1–3.5 cm long on petioles 2–5 mm, broadly rounded to base and apex, pinnately veined with 6 pairs, or seedlings 3-veined at base, shiny green above, paler below. Flowers Feb–Jun, on long pedicels in umbellate fascicles along short lateral secondary branches of a longer terminal main leafless axis 4–12 cm long. Mostly chaparral in northern and central Sierra Nevada, South Coast Ranges, Transverse Ranges, Peninsula Ranges. Kern Co.: CCH: Upper San Emigdio Canyon, rocky soil along a creek in a deep, shaded canyon bottom; shrub 10 ft tall, 6 ft across; corollas white, bark green, Twisselmann 23 Jun 1955 (CAS-399271. Annotated by Nancy Craft Coile 1989-01-01).

Ceanothus pauciflorus Sesse´ and Mociño ex A. P. de Candolle 1825. Not recognized to occur in Kern County. Considered by Burge and Zhukovsky (2013) to be the same as C. vestitus; however, C. vestitus is distinguished  here by the relatively small stipules in contrast to the goat-horn like stipules of C. pauciflorus.

Ceanothus perplexans W. Trelease 1897.  Cupleaf ceanothus. Shrub branched from base to 3 m; branches opposite, gray; persistent stipules conspicuous, especially in the southern California Floristic Province, asymmetrically conical, ± as wide as petiole at base (or wider), orange brown or dark brown to black, leaves evergreen, yellow green, opposite, in singles or fascicles of two or more, leathery, ± broad elliptical to round, more narrowly tapered to base than to apex, often truncated to apex, (5-) 10–20 (-28) mm, slightly folded upwards along mid nerve, or concave across the upper (adaxial) surface; margins prominently toothed; upper (adaxial) surface yellow green undersurface paler green, veins prominent, with or without scattered hair patches; flowers Mar–May, white (or blue), loosely clustered along a floral axis exceeding leaves.  Type from Yavapai County, Yampai Valley, Arizona (holotype GH!).  Kern Co.: CCH: Tehachapi (M.E. Jones, 20 May 1903 (POM85878); Summit Rd [Willow Springs Rd], 4800 ft, J.B. Spring  25 Aug 1930 (UC1070680), identified C. greggii var. perplexans.  These specimens, which I have not seen, may prove to be C. vestitus.

            Ceanothus perplexans is recognized to have forms with and without hair patches on the leaf undersurface. An  intermediate form of C. cf. vestitus on Mt. Pinos is recognized by the alignment of white flecks along lateral and mid veins, in contrast to a scattered growth in C. perplexans. The intermediate form is also evident in foothills west of Bishop, California, while both scattered and aligned pubescent forms occur in Arizona and in southern California.

Ceanothus pinetorum Coville 1893. Kern ceanothus.  Low evergreen rounded or matted shrubs to 2 m across, up to 1.5 m high; branches reddish brown, aging gray or glaucous, stipules persistent, conspicuous, conical, spreading from twigs, 1–2 mm wide, red orange, aging black, leaves holly-like, opposite, ± round in outline, 1–2 cm, margins spiny; flowers May–Jun, blue to lavender, on pedicels 5–8 mm in small umbellate fascicles (often 5 in number) on a short thick floral axis or stubby branch; immature fruit 6-lobed, pedicels swelling in fruit. Among granite outcrops or granitic soils, mixed conifer forests or Jeffrey pine forest, Klamath Mts., Trinity and Shasta cos., with a disjunct occurrence on the Kern Plateau in Tulare and Kern cos. (Fross & Wilken 2006). Not in Twisselmann. CCH records from the Southern Sierra Nevada region, Kern River Canyon near Durwood (Wogley, 30 May 1939. CCH) may be Durwood Creek in Tulare Co., also reported from the Upper Kern River south of the Forks of the Kern.  Image above from the southern Kern Plateau in Tulare Co. The species, which is related to C. cuneatus, is easily identified by its low rounded clump or mat habit with thick spiny margined leaves, strongly lobed fruit, and thickened fruiting pedicels.

Ceanothus vestitus Greene 1890 [Ceanothus greggii A. Gray 1853 var. vestitus McMinn 1939]. Similar to C. crassifolius var. planus in leaves having a white areolate undersurface, differing in the pattern of hairs around stomata crypts aligned along the lateral and mid veins. Type from “borders of the pine forest on the mountains near Tehachapi (US isotype!).”  Apparently rare in Kern County. Specimen images on SEINet.  California.  Inyo Co.: Birch Creek watershed, adjacent to McMurray Meadows road. 37.093333  -118.335833, uncommon, Artemisia tridentata, Purshia stansburyana, Ephedra nevadensis, 1800 m, McLaughlin, 17 May 2005 (ARIZ). Arizona.  Mohave Co.:  Cerbat Mts., juniper-oak wd, 4130 ft, G. K. Helmkamp, 11 Apr 1997 (DES);

            Ceanothus vestitus appears intermediate between C. perplexans and C. crassifolius var. planus. It was included under  C. vestitus by Fross & Wilken (2006) in which the type specimen would key to C. perplexans, not to C. vestitus.  McMinn (1939) thought the type for C. vestitus is a good match for that of  C. perplexans (C. greggii var. perplexans); its type—from Yavapai County, Arizona—was considered "problematic" by Burge & Zhukovsky (2013); however, it has since been designated holotype (Burge et al. 2015) . Thus, C. perplexans and C. crassifolius var. planus could be treated as synonyms or varieties of C. vestitus.

            In JM1 and other floras, Ceanothus vestitus was considered a variety of the widely distributed C. greggii,occurring from mainland Mexico to southwestern Utah and to the western edge of the California deserts and Transverse Ranges.  Ceanothus greggii var. greggii differed by leaves appearing convex above and densely white underneath and having slightly revolute margins; however, however, Burge and Zhukovsky (2013, 2015) concluded that C. pauciflorus and C. vestitus are not sufficiently distinct based on morphometric multivariate analysis of nine character features of leaves. They also mentioned a “suite” of character features that can be applied to distinguish the related C. perplexans Trelease 1897, which had been earlier treated as a variety of C. pauciflorus (C. greggii var. perplexans Jepson 1925).

Ceanothus cf. vestitus Greene 1890.  Mojave ceanothus. Shrub similar in habit to C. cuneatus; leaves often slightly longer and more tapered near base, sometimes with few small teeth along margin; flowers frequently in clusters at ends of branches; fruit usually shiny dull red, smooth without horns, sometimes with pimple-like projections in the mid region of each carpel, or with relatively short lateral flattened wart-like horns projecting at right angles from near base. Rocky slopes and ridges with open woodlands or forests from 3,000–7,700 ft (900–2,330 m), mountain slopes around the southern San Joaquin Valley, eastern slopes of the Sierra and Cascade ranges, mountains of the Mojave Desert east to New Mexico, southern Utah, northern Arizona (also possibly extending to southwestern Texas and Mexico (Fross and Wilken 2006). Kern Co.: “Common in the chaparral in the mountains mostly on the east slopes where it replaces C. cuneatus, and extending southwest of Mt. Abel and west to Kern Canyon.  In the Cache Peak region of the extreme northeastern Tehachapi Mountains, C. vestitus, C. cuneatus, and Quercus turbinella var. californica [Q. john-tuckeri] form an interesting and unusual chaparral on the steep arid slopes of the region”  (Twisselmann).  

The illustration of C. vestitus in McMinn (1942), referred to and presented by Fross and Wilken (2006), exemplifies C. cf. vestitus in addition to the images of plants shown from Kern County.  However, Ceanothus cf. vestitus described in this treatment could be given another name yet to be determined. The problem with subgenus Cerastes in Kern County seems to be distinguishing between Ceanothus cf. vestitus and C. cuneatus as evident from both names applied to specimens from the same general locations west of Walker Pass (CCH). Burge and Zhukovsky (2013) indicated further study is needed for southern California species of Cerastes that involve contact with C. cuneatus.  That would seem to be the case for Kern County.

The CCH specimens of C. vestitus cited by Burge and Zhukovsky (2013) from Kern County include those collected by Twisselmann and others from Walker Pass, Summit of Scodie Mt., 6 miles east of Claraville on road to Kelso Valley, along road from Alta Sierra to Wofford Heights, Secretario Canyon on the Tejon Ranch, west end of Tollgate Ridge in the mountains east of Keene, and San Emigdio Creek along the Old Potrero Road.  In another report by Burge and Mano (2011), they cited one specimen they collected of C. cuneatus in Kern Co. from “Clear Creek watershed, S of Ball Mountain and SE of Hooper Hill.” 

Jepson in his Manual of the California Flora  (1925) distinguished the species in his key by geography, C. greggii—found along the western border of the Mojave Desert vs. “cismontane” for C. cuneatus. Jepson listed C. vestitus as a synonym of C. greggii, but recognized var. perplexans. Thus, the conclusion reached by Burge and Zhukovsky (2013) hardly differs from that already reached  long ago by Jepson (1925) except for the name, C. pauciflorus. The latter was distinguished by Fross and Wilken (2006) by the dense growth of white hairs on the undersurface of the leaves to the extent that the veins are not visible as also recognized in part by Burge and Zhukovsky (2013). Some plants in Kern Canyon appear similar in leaf characteristic but lack the prominent stipules of  C. pauciflorus.

Generally, Ceanothus pauciflorus (Burge 1026a (DUKE, topotype) differs from C. vestitus (isotype, US) by the larger stipules. The California plants referred to Ceanothus cf. vestitus have relatively small stipules. They (C. vestitus) occur across the desert mountains of California to Arizona.  Some plants appear to have orange stipules, while stipules in other plants appear black. The image from Mt. Pinos in Kern Co. appears intermediate to C. perplexans, also shown above from near Bishop in Inyo Co.  Ceanothus perplexan differs in the absence of hairs on twigs.

Pharmacological References

Ceanothus americanus

Klein F. K. and H. Rapoport.  1968. Ceanothus alkaloids. Americine. J. Am. Chem. Soc. 90(9): 2398–2404.