Usnea lapponica Vain., 1925
| Common name | Powdered Beard | Code: USNELAP
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|---|---|---|
| Field Characters | Fruticose, shrub-like chlorolichen. Thallus shrubby to subpendulous, with yellowish green divergent branches. Papillae numerous. Base blackened or the same color as the thallus. Soralia conspicuous, larger than half branch diameter when mature, deeply excavate, typically reaching the central axis and tearing off the adjacent cortex. Soralia often bordered by loose cortical “flaps”. Isidia absent, apothecia extremely rare, and pycnidia unknown. | |
| Similar species |
Usnea substerilis: historically considered distinct because of the presence of at least some isidia, and soralia that are not as excavate. Based on phylogenetic analyses where isolates from these two species are polyphyletic and intermixed, many authors have lumped these two species under the name Usnea perplexans. Molecular work with Alberta material is required before we do likewise.
Usnea glabrescens: soralia very round and wide with well-formed thalline rim. |
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| Ecology | Very common in Alberta. Found on both deciduous and confer trees across the forested regions of the province. | |
| Chemistry | Cortex KC+ yellow, K- or K+ pale yellow, C-, PD-, UV- (usnic acid). Medulla K+ yellow to red, PD+ orange to yellow (salazinic, ± caperatic, ± protocetraric (trace) acids) or K-, PD+ yellow (psoromic, 2’-O-demethylpsoromic acids) or K-, PD- (no secondary substances) | |
| Molecular support |
Weak at species-level. Clades in a multi-locus phylogeny do not correspond to traditionally circumscribed species. Because of the lack of resolution in a clade of U. lapponica, U. substerilis, U. barbata, and U. intermedia, Mark et al. (2016b) placed U. substerilis in synonymy with U. lapponica. Lucking et al. (2020) similarly found that there was no evidence for the separation of U. lapponica from U. substerilis. However, Clerc & Naciri (2021) conclude that specimens used in these studies were of insufficient quality and thus suggest that the synonymization of U. lapponica and U. substerilis should not be accepted. Synonymy not adopted at this time; no new sequences generated. | |
| Links | ||
| Gallery |
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- Usnea lapponica close up of soralia. ABMI Collection
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- Usnea lapponica close up anatomical ratios. ABMI Collection
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- Usnea lapponica branching. ABMI Collection
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- Usnea lapponica close up of soralia. UBC Collection
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- Usnea lapponica form. UBC Collection
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- Usnea lapponica branch tips. UBC Collection
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- Usnea lapponica base. UBC Collection
