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Vermilacinia varicosa
''Vermilacinia varicosa'' is a fruticose lichen known from two islands along the Pacific Coast of central Baja California, Isla San Roque located just off the southern Vizcaíno Peninsula west of Bahía Asuncón 〔Mapcarta, Isla San Roque, retrieved 1 Dec 2014, http://mapcarta.com/20389392〕 and Cedros Island where found on precipitous rocks along the northwest coast. The epithet, ''varicosa'', is in reference to the unusually dilated type of branch in the genus. The lichen was first collected by Joseph Nelson Rose on 15 March 1911 during the ''Albatross'' Expedition.〔Towsend,. C. H. 1916. Voyage of the U.S.S. Albatross in Lower California Seas. Cruise of 1911. Bulletin of the American Museum of Natural History 35: 399–476〕 His lichen specimens had been kept separate from the mounted and filed lichen collections in the herbarium at the Smithsonian Institution, Department of Botany, US)〔US is the acronym for the United States National Herbarium as standardized by the Index Herbariorum, http://sciweb.nybg.org/science2/IndexHerbariorum.asp〕 loose in brown standard herbarium paper, and were made available to Richard Spjut sometime after 1986 while he was undertaking a revision of the genus ''Niebla''〔Spjut, R. W. 1996. ''Niebla'' and ''Vermilacinia'' (Ramalinaceae) from California and Baja California. Sida〕
==Distinguishing Features==
''Vermilacinia varicosa'' is classified in subgenus ''Vermilacinia'' in which it is distinguished from related species by its thallus divided into relatively few fan-shaped branches (less than 10)—widely expanded above a short narrow stalk-like base—and by its secondary metabolites of terpenoid compounds that generally characterize the subgenus: an unknown T3, the triterpene zeorin and the diterpene (-)-16 α-hydroxykaurane, with an accessory β-orcinol depsidone, salazinic acid.〔 The broadly expanded branches from base to apex is similar to ''V. robusta'', which differs by its thallus divided into tubular shaped branches, but it is difficult to judge from pressed specimens to what degree branches of ''V. varicosa'' are inflated in its natural form.
''Vermilacinia rosei'', also collected by Rose from Isla San Roque, appears morphologically indistinguishable, differing only in chemistry of the triterpenes, which have taxonomic significance from a phytogeography point of view〔 ''Vermilacinia johncassadyi'', for example, which has the T1,T2 triterpenes, and is found only in the Vizcaíno Desert, is morphologically similar but geographical separated from ''V. laevigata'', a species of the California Floristic Province that differs morphologically by stalked apothecia and chemically by the lichens substances generally found in the subgenus.〔 ''Vermilacinia cedrosensis'' and ''V. reptilioderma'' are similar species with the same chemotype differences but are not geographically separated, however, they show slight differences in cortical features; while their taxonomic distinction is complicated by the related species ''V. paleoderma'' and ''V. polymorpha'' that overlap only partly in their geographical distribution. Emphasis has been given to chemical characters because they correlate with known phytogeographical and ecological differences in vascular plants as outlined in Richard Spjut’s introduction and taxonomic keys to the species.〔 This is in contrast to Peter Bowler and Janet Marsh who felt the “chemical based taxonomy of the 1940’s–1960’s” was history, which should be abandoned;〔Bowler, P. and J. Marsh. 2004. "Niebla". ‘Lichen Flora of the Greater Sonoran Desert 2’: 368–380.〕 however, the trend now is to favor more species; for example, 126 species were recognized from a single lichen species.〔Robert Lücking, Manuela Dal-Forno, Masoumeh Sikaroodi, Patrick M. Gillevet, Frank Bungartz, Bibiana Moncada, Alba Yánez-Ayabaca, José Luis Chaves, Luis Fernando Coca, and James D. Lawrey. 2014. A single macrolichen constitutes hundreds of unrecognized species. PNAS 111(30): 11091–11096〕
The triterpenes T1,T2 appear as major lichen substances in thin-layer chromatography. Lacking DNA phylogeny data, and detailed knowledge of their biosynthetic pathways, which in this case appears to involve the mevalonic acid pathway,〔 it is difficult to determine whether the terpenes (T1,T2) are additive, or are an ancestral trait to the other compounds more widely distributed in the subgenus Vermilacinia.
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