Josef Hafellner first informally separated the moss-dwelling "Rhyparizae" species from Bryonora in the early 1990s, coining the name Bryodina, but the genus became nomenclaturally valid only in 2001 when he published a full Latin diagnosis and typified it with Bryodina rhypariza.[3] The genus sits in the family Lecanoraceae (order Lecanorales) and is typified by Bryodina rhypariza (originally described as Lecanora rhypariza by William Nylander in 1860[4]).[3] A second member is the Himalayan species B.selenospora. Hafellner highlighted several anatomical distinctions from Bryonora in the strict sense: the apothecial margin is grey-brown and resembles that of some Rinodina species, the cortex around the apothecium carries coarse granules , and a cup-shaped layer of intricately woven hyphae separates the hymenial tissue from the thalline exciple . Bryodina spores are thin-walled, kidney- to sausage-shaped and usually curved, whereas those of Bryonora are thicker and more barrel-like. The generic name combines the Greek bryon ('moss')—reflecting its substrate preference—with the ending "-dina", chosen to evoke its superficial resemblance to Rinodina.[3]
Description
The lichen forms a thin, crustose thallus that spreads over siliceous rock or the cushions of moss that colonise such stone. Apothecia are lecanorine : the disc and margin are differently coloured, the latter retaining a thin rim of thallus tissue (the thalline margin ). Discs range from pale to mid-brown and sit flush with, or only slightly above, the surrounding crust. Beneath the hymenium lies a distinctive "intricata" layer—an intricate tangle of hyphae that behaves like a tiny cup, isolating the fertile tissue from the thalline margin. The exciple itself displays coarse granules that are visible in thin sections.[3]
Asci follow the Lecanora-type blueprint: eight ascospores, a strongly iodine-positive (eu-amyloid) tholus , and a broad central mass that also stains blue in iodine. Spores are initially single-celled but may develop one septum with age; they are oblong, gently kidney-shaped or stoutly bacilliform , and have thin, parallel walls—features that help separate the genus from lookalikes. No specialised asexual propagules have been reported in Bryodina, and secondary metabolite data are lacking.[3]
Habitat and distribution
Bryodina species colonise siliceous substrates in cool, rather open situations where mosses form persistent mats. The type species is widespread, though scattered, on nutrient-poor sandstone and granite outcrops in temperate parts of Europe, while B.selenospora occupies comparable habitats on Himalayan boulders. Both appear to rely on the micro-climatic buffering provided by the moss layer, and neither has yet been confirmed from calcareous or heavily shaded sites.[3]
↑ Nylander, W. (1860). "Novitiae quaedam licheneae Norvegicae"[Some new lichens of Norway]. Öfversigt af Kongl. Vetenskaps-Akademiens Förhandlingar (in Latin). 17: 295–297.
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