Niebla disrupta

©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
October 2005, Sep 2012

Niebla and Vermilacinia (Ramalinaceae) from California and Baja California.  
Spjut, R.W., 1996. ISSN 0833-1475, 208 pp.  
Sida, Botanical Miscellany 14. Botanical Research Institute of Texas, Inc.

 

Marin Co., Pt. Reyes, CA,
L. E. Rose,
16 Jul 1952
TLC: Sekikaic acid & triterpenes, 3 Sep 1993

Marin Co., Pt. Reyes, CA
V. Ahmadjian, 20 May 1966
TLC: Sekikaic acid & triterpenes, 1 Sep 1993

Tomales Bay, near Marshall, CA
Cooke & Cooke, 16 Jul 1942
TLC: Sekikaic acid & triterpenes, 3 Sep 1993

Pt. San Pedro, San Mateo Co., CA
Herre & Doty 3332, 22 May 1942
(L75743, L74403, COLO)

 

Marin Co., Willow Camp, CA
H. E. Parks 2733,
25 Apr 1925
TLC: Sekikaic acid & triterpenes, 3 Sep 1993

 

Niebla disrupta, Lectotype
 

 

Niebla disrupta
Santa Barbara Island
Bratt 5182
, Jan 1987.
 

 

     Niebla disrupta is a lichen endemic to coastal areas of California. The geographical range of N. disrupta partially overlaps with N. homalea—in the California islands from Isla Guadalupe to the Cannel Islands—and on the mainland from San Luis Obispo to Mendocino Cos. It is notably absent south of Morro Bay.

     At first glance, Niebla disrupta seems to hardly differ from N. homalea, but they are easily distinguished by their secondary metabolites, sekikaic acid in N. disrupta, divaricatic acid in N. homalea.  Despite their similar morphology, chemistry, and geographical distribution, they are not considered sibling species.

     Niebla disrupta is also recognized by the terminal whip-like, often sharply pointed branchlets, usually with undeveloped apothecia, while mature apothecia are to be found below—near the base of the thallus.  The whip-like branches often change direction where apothecia initiate. Niebla homalea, in contrast, has mostly ribbon like branches with apothecia maturing nearer the apex, usually on a short broad lobe shaped much like the branch itself.  Both species may occur together as evident from herbarium collections.

     Variants assigned to this species include specimens collected by Charis Bratt 5182 from Santa Barbara Island and by Reifner 86-25 (Fig. 8.4 in Spjut 1996) from Morro Bay, and possibly a Stephen Sharnoff  photo titled “Niebla homalea 4” reportedly taken on Santa Rosa Island. These 'disruptoid' nieblas, which share the terminal whip like branches with subterminal apothecia, are similar to N. suffnessii that differs by the more rounded branches in x-section with a thinner cortex; however, they appear to belong to a separate undescribed southern California species complex that includes variants of N. cornea, N. dissecta, N. laminaria, and possibly N. lobulata, which has not been recognized from California.

     The two Niebla disrupta variant specimens mentioned above have an irregular network of cortical ridges between branch margins in which the branches appear 3–4 angled in cross section as seen in N. dissecta, a species recognized by a broader than tall thallus and terminal wide-spreading branchlets arising from dilated branches. The apothecia are larger and positioned more on the face of the branch rather than perpendicular to an expanded margin of the branch.  They are referred to N. disrupta by the thallus appearing taller than wide, and by the terminal whip-like branches as just noted.  This variation may be a product of geographical (evolutionary) differentiation of N. disrupta south of Monterrey Co. that involved  genetic exchange with variants of N. cornea occurring further south and on Santa Barbara Island, N. laminaria at Pt. Loma, and N. aff. lobulata in the Santa Monica Mts.

     A related sekikaic acid species, Niebla fimbriata, has spindle-shaped branchlets that are relatively straight in a wind-swept appearance along one or both margins of an aching branch, analogous to “scorpiod cyme” type of inflorescence in angiosperms.

      The sekikaic-acid species considered most similar to N. disrupta are Niebla cornea and N. dissecta. They are distinguished in the following table, diagnostic characters in bold type.

 Character

N. disrupta

N. cornea

N. dissecta

 

 

 

 

Branching general

Anisotomic.

Anisotomic.

Anisotomic.

Terminal bifurcate
branches

Usually not evident.

Bifurcate and rabbit-like ear-lobes, or trifurcate with unequal lobes, or often expanded with digitate-like segments

Common, antler-like, often 3-pointer in one division, 2-pointer on other, more flattened and digitate in type

Branch shape lengthwise

Sublinear.

Scoop-like to ribbon-like

Sublinear with expanded lobes, especially near apex.

Branch shape cross-section

Elliptic or 3–4 angled in one variant

Elliptic.

Prismatic, or ±4-angled.

Branches twist

Frequent between base and apex.

Irregularly twisted or not twisted, often irregularly contorted.

Frequent between base and apex.

Branch margin

Usually well-defined,  acute.

Rounded to acute, sometimes thickened.

Variable.

Cortex

Glassy, transversely cracked at various intervals.

Mostly smooth, irregularly transversely cracked or reticulate ridged

Dull, transversely cracked and reticulate ribbed with tertiary longitudinal sinuous ridges between the margins.

Apothecia

Subterminal undeveloped apothecia on long whip-like branches, mature apothecia often on lower short lateral branches, oriented perpendicular to branch margins, shorter branches often at nearly right angles.

Terminal in small loose aggregates, often in 4's on short lobes of an  expanded branch, or sessile and in plane with the main branch.

Generally most developed near base of thallus, sessile, submarginal.