Lempholemma radiatum (Sommerf.) Henssen

Ber. deutsch. bot. Ges., 81: 176, 1968. Basionym: Collema radiatum Sommerf. - Suppl. Fl. Lapp.: 121, 1826
Synonyms: Collema lichinodeum Nyl. ex Cromb.; Omphalaria radiata (Sommerf.) Forssell; Synalissa lichinodea (Nyl. ex Cromb.) Arnold; Thyrea radiata (Sommerf.) Zahlbr.
Distribution:
Description: Thallus foliose, loosely attached, dark green and gelatinous when wet, black and hard when dry, with radiating, usually divergent, linear and strap-shaped, sometimes weakly channelled, 5-8 mm long, 0.3-0.8(-1) mm wide, sparingly dichotomously branched lobes, forming up to 3 cm wide rosettes. Central parts of thallus with clusters of globose to clavate isidia-like outgrowths, sometimes also with globose hormocystangia producing hormocysts measuring c. 30 x 10 μm. Lower surface paler, with tufts of white hapters. Apothecia extremely rare (not known in European material), immersed in the thallus, with a pore-like, up to 0.3 mm wide, brown disc, developing from ascogones arising beneath pycnidia (pycnoascocarps). Asci 8-spored, clavate to cylindrical, with a very thin wall disintegrating or opening by apical ruptures, Lichina-type. Ascospores 1-celled, hyaline, broadly ellipsoid, 14-23 x 8-12 μm. Pycnidia rather frequent, immersed. Conidia simple, hyaline, bacilliform, sometimes swollen at one or at both ends, 3.5-5.5 x c. 1 μm. Photobiont cyanobacterial (Nostoc, in disintegrating chains, the individual cells 4.5-5.5 μm wide). Spot tests: all negative. Chemistry: without lichen substances.
Note: on long-time moist, mostly calcareous rocks, often amongst bryophytes, near and above treeline; known from cool to cold parts of the Holarctic region, with a few records from the Eastern Alps (Austria). To be looked for in the Italian Alps.
Growth form: Foliose

Substrata: rocks, soil, terricolous mosses, and plant debris
Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)

pH of the substrata:

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Altitudinal distribution:

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Predictive model

Samul Brinker – CC-BY-SA NC – Source: https://www.inaturalist.org/taxa/223163-Lempholemma-radiatum



Curtis Randall Björk – CC BY-SA 4.0
Nunavut, Devon Island, Basecamp Lowlands Terricolous in tundra



Curtis Randall Björk CC BY-SA 4.0
Nunavut, Continental Central Canadian Arctic, Hope Bay. Terricolous in rocky tundra near marine shore
2014-07-00



Curtis Randall Björk – CC BY-SA 4.0
Nunavut, Continental Central Canadian Arctic, Hope Bay Date: 2014-07-00 Terricolous in rocky tundra near marine shore