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.

Evolutionary history of coastal species of fog lichen genera
Niebla, Ramalina and Vermilacinia
Emmanuel Sérusiaux & Richard  Spjut
Baja California, Jan-Feb 2016

Evolution and diversification of Niebla
Steve Leavitt et al., Baja California, Dec 2016

 N of Punta San Rosallilita, Canyon de San Andrés, N 28°42.624, W 114°16.193, 1 m.
Spjut & Sérusiaux 17114. Jan 2016

Vicinity of Punta Catarina, south of point, on gypsum-based badlands.
Leavitt et al. 16-1035, Dec 2016
 

Vizcaíno Peninsula, road
 to Punta Eugenia, 
Spjut & Marin 10560
Apr 1989

Bahía de Santa María
Spjut & Marin 11377
Apr 1990

 W of Rancho San Andrés
~100 km N of Guerrero Negro, Spjut & Marin 9073
May 1985

W of Rancho San Andrés
~100 km N of Guerrero Negro, Spjut 9887A
May 1986

N. caespitosa x N. podetiaforma?
~100 km N of Guerrero Negro
 between Punta Prieta
and Punta Rocosa,on ridge, Spjut 9971, May 1986

Punta Canoas, lower steps
of mesa near the ocean, on
red pumice, Spjut 11230,
Apr 1990

N. caespitosa x N. marinii? Punta Canoas, lower steps
of mesa near the ocean, on
red pumice, Spjut 11231,
Apr 1990

Ridge N of Punta Rocosa, BCN
Spjut 10300, Mar 1988

Mesa W of Pico Santa Monica, Rancho San Francisco
de la Sierra, 325 m elev.
 Spjut & Marin 10921 Apr 1989

Santa Cruz Island
Bratt 2303

San Clemente Island
Santesson 18043, isotype (COLO)

Geographical Distribution

     Niebla caespitosa is a lichen that is widely distributed along the Pacific Coast from the southern California Channel Islands to the Vizcaíno Peninsula region of Baja California. It is identified by the lichen substance of divaricatic acid (with triterpenes), and by the thallus divided into small tufts of flattened contorted branches.  Near the thallus base the branches are usually short and  blade-like; above they dilate and ± digitately divide into shorter branchlets. The dilated parts of branches generally appear fringed and contorted due to a relatively thin cortex, in contrast to the thicker cortex on the more rigid thallus of N. testudinaria with stiffly erect branchlets, often short bifurcate near apex

     Niebla caespitosa is most common in the southern part of the northern Baja peninsula along the coastal mountains between Punta Rocosa and Punta Rosarito, and along the eastern Vizcaíno Peninsula on the edge of the mesa escarpment, where occurring with Vermilacinia cedrosensis.  On the southern part of the BCN peninsula near Rancho San Andrés, N. caespitosa often occurs with N. flabellata (salazinic acid) and N. flagelliforma (divaricatic acid).

     Niebla caespitosa appears to intergrade with N. flagelliforma on the rock walls of a narrow arroyo near Rancho San André in the southern part of Baja California Norte, ~100 km north Guerrero Negro.  As indicated above N. flagelliforma is generally recognized by terminal digitately arranged flagelliform branchlets with a thinner cortex that develop from a wider thicker cortical lower primary branch. The cortex of N. caespitosa, in contrast, is more uniform in thickness in which the branchlets ± appear equally contorted throughout with less regularity to their shape.

    Niebla caespitosa may be confused with Niebla dilatata (divaricatic acid), which is distinguished by its larger thallus having rounded  marginal lobes (lobulate) instead of the lacerated margins that characterizes N. caespitosa.  The lobulate margins of N. dilatata are usually thickened by undeveloped apothecia and pycnidia. Niebla flabellata  (salazinic acid) and N. spatulata (hypoprotocetraric acid) are similar in their flattened lacerated branches, but easily distinguished by their lichen substances.

      A putative hybrid with N. undulata is indicated above for Spjut 11231 that was collected on a step of an escarpment leading up to a mesa northwest of Punta Canoas.  Niebla caespitosa generally has transversely oriented cortical ridging near apex, and while this putative hybrid has the apical longitudinal ridging associated with N. undulata, its branches are not particularly undulate along margins, nor do they show the flattened digitate branching of N. caespitosa.  It was collected in association with N. caespitosa (11230), N. flagelliforma (11232), N. infundibula (11229), N. siphonoloba (11226), N. marinii (11227, 11236), and N. effusa (11234).  The conspicuous and abundant dark pycnidia indicate affinities to N. marinii, which differs by having salazinic acid and horseshoe-like terminal branches.