Usnea cavernosa (Ach.) Tuck., 1850
| Common name | Pitted Beard | Code: USNECAV
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|---|---|---|
| Field Characters | Fruticose, hair-like chlorolichen. Thallus pendant, to 60cm long, branching sparingly and dichotomously. Main branches slender, weakly to strongly ridged and foveolate, lacking papillae. Thin, elongate pseudocyphellae often present. Base is pale but often missing, and thalli are often found draping over branches. Terminal branches sinuous. Cortex thin, medulla lax, elastic central axis present but often weakly formed. Soralia and isidia lacking. Apothecia relatively uncommon. | |
| Similar species |
Alectoria sarmentosa: lacks a central cord, outer cortex more ridid, thalli more wiry and stiff.
Evernia divaricata: lacks a central cord, but can have a thickened inner medulla that resembles a cord. Branches more irregularly with abundant spiny side branches, branches flabbier and wider. Usnea cavernosa is distinctive from other pendant Usnea spp. such as U. scabrata and U. dasopoga due to its lack of papillae and soralia. |
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| Ecology | Common in spruce and mixedwood stands in the boreal and foothills regions, often found on conifers. | |
| Chemistry | Cortex KC+ yellow, K- or K+ pale yellow, C-, UV- (usnic acid). Medulla K+ yellow to red, PD+ yellow (salazinic acid) or rarely K-, PD-. | |
| Molecular support |
Strong support at the species level. Accessions from the USA and Switzerland formed a strongly supported monophyletic clade in multi-locus phylogenetic study by Mark et al. (2016b). | |
| Links | ||
| Gallery |
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- Usnea cavernosa close up of branch foveoles. ABMI Collection
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- Usnea cavernosa close up of anatomical proportions. ABMI Collection
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- Usnea cavernosa. ABMI Collection
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- Usnea cavernosa. UBC Collection
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- Usnea cavernosa. UBC Collection
