''Niebla homaleoides '' is a

fruticose lichen A fruticose lichen is a form of lichen fungi that is characterized by a coral-like shrubby or bushy growth structure. It is formed from a symbiotic relationship of a photobiont such as green algae or less commonly cyanobacteria and one, two or mor ...

that grows on rocks within a narrow region of the foggy Pacific Coast of

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

in the Northern Vizcaíno Desert, Arroyo Sauces, Punta Cono and ridges south of Punta Negra.Spjut, R. W. 1996. ''Niebla'' and ''Vermilacinia'' (Ramalinaceae) from California and Baja California. Sida Bot. Misc. 14 The epithet, ''homaleoides'' is in reference to the similarity to ''

Niebla homalea ''Niebla homalea'' is a species of fruticose lichen that grows on rocks in foggy areas along the Pacific Coast of North America, from Mendocino County, California south to Bahía de San Quintín on the main peninsula of Baja California, with an ...

''.

Distinguishing features

''Niebla homaleoides'' is characterized by a rigid

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

divided into sub eretemostly strap-shaped branches spreading from a holdfast, to 8 cm high, and by the absence of lichen substances except usnic acid and an unknown suspected to be a scabrosin derivative. The species is best identified by chromatography such as high-performance liquid chromatography or thin-layer chromatography. The cortex generally resembles that of '' Niebla cornea'', whereas comb-like branchlets on some thalli are similar to those of ''

Niebla josecuervoi ''Niebla josecuervoi '' is a fruticose lichen that grows on rock, stony soil and sand along the Pacific Coast of northern Baja California from near Misión San Vicente Ferrer to Punta Santa Rosalilillita.Spjut, R. W. 1996. ''Niebla'' and ''Ve ...

''. Other thalli that have flattened branches are similar to ''

Niebla flabellata ''Niebla flabellata '' is a fruticose lichen that grows on rocks along the foggy Pacific Coast of Baja California in the Northern Vizcaíno Desert, from San Fernando Canyon to the northern shore of the Vizcaíno Peninsula west to Cedros Island ...

''. Pycnidia are prominent on the upper parts of branches, and appear to be among the largest in the genus, but comparative measurements are not available for all species of ''Niebla''. ''Niebla homaleoides'' is related to the depsidone species within the genus by the absence of triterpenes, most closely to

salazinic acid Salazinic acid is a depsidone with a lactone ring. It is found in some lichens, and is especially prevalent in ''Parmotrema'' and ''Bulbothrix'', where its presence or absence is often used to help classify species in those genera. History I ...

-containing species by the presence of an unknown, possibly scabrosin derivative. This lichen

chemotype A chemotype (sometimes chemovar) is a chemically distinct entity in a plant or microorganism, with differences in the composition of the secondary metabolites. Minor genetic and epigenetic changes with little or no effect on morphology or anatomy m ...

is found in the related ''

'', ''

'', and ''

Niebla marinii ''Niebla marinii'' is a fruticose lichen that grows on lava along the Pacific Coast of Baja California from near San Fernando Canyon south to Morro Santo Domingo.Spjut, R. W. 1996. ''Niebla'' and ''Vermilacinia'' (Ramalinaceae) from Californi ...

''. Scabrosin esters isolated from the lichen ''

Xanthoparmelia ''Xanthoparmelia'' (commonly known as green rock shields or rock-shield lichens) is a genus of foliose lichen in the family Parmeliaceae.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, ''Xanthoparmelia'' is syn ...

scabrosa'' have shown activity against human tumor cell lines at nanomolar concentrations.

Taxonomic history

''Niebla homaleoides'' was discovered by Richard Spjut, accompanied by Richard Marin and Thomas McCloud, on 19 May 1986 just south of Punta Negra on rock outcrops on a ridge that appeared to receive more precipitation from ocean fog than other nearby areas (Plate 1D in Spjut’s 1996 revision of ''Niebla'' and ''Vermilacinia''). This particular ridge was observed during May 1985 by Spjut—while he and Marin were collecting samples of lichens in search of new drugs to treat HIV—to have fog lingering around the peaks most of the day. The following year, in May 1986, a special effort was made to find a path to the ridges and peaks. In addition to ''Niebla homaleoides'', other rare new species of lichens were discovered, ''

Niebla infundibula ''Niebla infundibula'' is a fruticose lichen that grows on rocks along the Pacific Coast in the Channel Islands of California (San Nicolas Island) and in Baja California on Guadalupe Island, and on the main peninsula in the southern region of th ...

'' (divaricatic acid) and '' Vermilacinia rigida''. Except for ''N. infundibula'', the species were also found on Punta Cono, 15 April 1990. A strong similarity of the Nieblas—and one other species on the same rock outcrop, ''

'' (salazinic acid)—is suggested to be the result of hybridization, and also at another location, Arroyo Sauces, with ''

'', a species that is characterized by a flattened branch morphology. The prominence of the pycnidia and their potential role in sexual reproduction has to be considered.Sanders, W. B. 2014. Complete life cycle of the lichen fungus ''Calopadia puiggarii'' (Pilocarpaceae, Ascomycetes) documented in situ: Propagule dispersal, establishment of symbiosis, thallus development, and formation of sexual and asexual reproductive structures. Am. J. Bot. , online ahead of print, 30 Oct 2014

References

{{Taxonbar, from=Q20720387 Lichen species Lichens of North America Ramalinaceae Lichens described in 1996 Taxa named by Richard Wayne Spjut