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Lepraria humida Š. Slavíková & Orange |
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Nomenclatural data
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Lichenologist 38(6): 505 (2006); type: United Kingdom, Wales, Merioneth (V.C. 48), Rhyd-y-sarn, south of Clogwyn y Geifr, 25 January 2005, A. Orange 15754 (PRA—holotypus, BG, NMW—isotypi; GenBank accession no. DQ401101).
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Morphology
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Thallus crustose, leprose, with powdery appearance; grey-green to whitish green; thin to thick; shape usually irregular; margin diffuse or delimited, lobes absent; cortex absent; true medulla absent; hypothallus weakly developed, hyphae below thallus sparse, pale orange-brown, lower surface absent; prothallus absent; areoles absent; squamules absent; soredia abundant, mostly fine to medium sized, 40-100(-160) µm in diam., relatively densely packed; projecting hyphae absent; isidia-like structures absent. Photobiont chlorococcoid.
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Chemistry
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The usual chemotype contains (1) atranorin, jackinic/rangiformic acid, norjackinic/norrangiformic acid ± (minor), angardianic/roccellic acid ± (minor), unknown anthraquinones ± (minor, in subthalline hyphae only); sometimes (2) stictic and constictic acids have been found in addition to usual substances, but were interpreted as contamination by Slavíková-Bayerová & Orange (2006). K+ yellowish, hyphae below thallus K+ purple-red, C–, Pd– or + yellow.
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Remarks
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According to molecular studies, L. humida is distinct from L. jackii and close to L. atlantica, thus belonging to the extended L. neglecta group (Ekman & Tønsberg 2002, Slavíková-Bayerová & Orange 2006, Slavíková-Bayerová & Fehrer 2007, Fehrer et al. unpublished). Morphologically similar species include L. jackii, L. neojackii, L. toensbergiana, L. sylvicola and especially L. atlantica and L. elobata. L. humida is distinct by its chemistry, especially anthraquinones in subthalline hyphae, and ecology. L. bergensis also contains anthraquinones but in that species, anthraquinones are usually abundant in the underside of thallus, while in L. humida they are confined to patches of subthalline hyphae (Slavíková-Bayerová & Orange 2006).
Slavíková-Bayerová & Orange (2006) also reported sp. H which was said to be morphologically and chemically identical to L. humida but distinct in ITS sequences, growing on rain-sheltered siliceous rocks, over moss, rarely on bark in Western to Central Europe. Slavíková-Bayerová & Fehrer (2007) added sp. BG of same morphological and chemical features, growing on damp siliceous rock in Bulgaria. See also discussion under L. jackii.
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Ecology and distribution
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Substrate and ecology: siliceous rocks, often between mosses; rain-sheltered damp surfaces. Distribution: British Isles.
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