''Letharia columbiana ''(common name brown-eye wolf lichen, synonyms ''Letharia californica'', ''Borrera columbiana'') is a common

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. It is in the family

Parmeliaceae The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: '' Xanthoparmelia'' ( 822 ...

, and the genus '' Letharia''. Its characteristics include a bright citron color, “brown-eyes”, and rounded, irregular branches. Though previously believed to lump together several lineages such as ''Letharia gracilis'' and others, there now exists more specific characteristics to identify the species. This lichen grows on the bark of

conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

s a couple inches tall. ''L. Columbiana''’s cousin, ''Letharia vulpina ''(common name wolf lichen), has similar geographical distribution and morphological features, with the major difference being the “brown-eyes” of ''L. columbiana''.

Habitat and distribution

''L. columbiana'' has a healthy distribution in subalpine forests of the United States and Canada, and are common on “high plateaus and ridges to timberline, occasional in low-elevation forests”. The same researcher cataloged the prevalence of this species throughout the Pacific Northwest, though it seemed to avoid the immediate coastline. Another article found them to be "ranging from the southern portion of British Columbia south to California and southwest through northern Idaho and western Montana".

Taxonomy and similar species

This species was first described in 1834 as the only lichen in a paper by Thomas Nuttall. Letharia vulpina JHollinger crop

''Letharia'', a fruticose genus of lichenized

Ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defi ...

s, was historically believed to include only ''L. vulpina'' and ''L. columbiana''. However, in 2016 an article published in The Lichenologist used molecular sequencing data to settle taxonomic differences within Letharia. Their results showed independence of four different species that had previously been described under ''L. columbiana''. ''L. gracilis'' had already achieved species recognition, and the article described for ''L. lucida'', while advocating for formal recognition of ''L. barbata'' and ''L. rugosa'', following additional studies of “diagnostic characters, ecological preference, and distributions”. These species have similar geographical distributions and habitats. ''L. columbiana'' is frequently incorrectly identified as ''

Vulpicida canadensis ''Vulpicida'' is a genus of lichenized fungi in the family Parmeliaceae. Circumscribed in 1993 to contain species formerly placed in ''Cetraria'', the genus is widespread in Arctic to northern temperate regions, and contains six species. The genu ...

'' (common name Brown-eyed Sunshine Lichen, another wolf lichen), due to similar surface coloring and the same brown-eye structures. However, this species has a more flattened, round surface.

Description

Sharing the common characteristics of lichens, this Ascomycete grows 3–11 cm from the bark on which it is attached. The intricate and divaricate ramified thallus produces these irregular branches, 0.5–3 mm wide, with uneven thickness, and a bright yellow-green color. In the midst of these spiky branches are the “brown eyes”, or the fruiting bodies, whose function it is to make spores for reproduction. ''L. vulpina'' has no such brown eyes or spores and therefore does not reproduce sexually. This is one way to differentiate the two species.

Life cycle and reproduction

Lichens are a combination of fungus and algae (sometimes cyanobacteria), but only the fungus reproduces sexually with the presence of spores. The new ascospores now need to find a symbiotic relationship with a new algal species. ''L. columbiana'' lacks abundant asexual structures, and in turn bears apothecia, a type of

Ascocarp An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are m ...

. Apothecium is a wide, saucer-like fruiting body containing three parts: a hymenium, hypothecium, and excipulum. The hymenium consisting of asci is the fertile layer of the structure. Different apothecia may employ different dispersal strategies, and therefore the arrangement of asci within them may be different, but there is not sufficient research on the asci of ''L. columbiana'' to determine their arrangements.

Vulpinic Acid

A common characteristic of ''Letharia'' is the presence of

vulpinic acid Vulpinic acid is a natural product first found in and important in the symbiosis underlying the biology of lichens. It is a simple methyl ester derivative of its parent compound, pulvinic acid, and a close relative of pulvinone, both of which ...

, a secondary metabolite of the symbiosis between fungi and algae. Its biological function is hypothesized to be a repellant against grazing herbivores. ''L. columbiana'' was used for its vulpinic acid, by Native Americans and Northern Europeans for poison-tipped arrows. Vulpinic acid is poisonous to all meat-eaters such as humans and carnivorous mammals, but not to rodents. Some other Natives Americans used the lichen in medicine, balms, or as a source of dyeing water with its recognizable bright-yellow color.

Ecological Impact

Observing the ecological implications of lichens allows scientists to study the health of conifer forests. Due to the positive correlation between forest age and lichen biomass, lichen diversity and abundance are highly dependent on preserving habitats and existing ''L. columbiana'' populations. Human mediated dispersal is a suggested method of propagation and maintaining the health of the species.

References

{{Taxonbar, from=Q10559851 Lichen species Parmeliaceae