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Collema substellatum H. Magn.
Family: Collemataceae
Collema substellatum image
Degelius, G 1974: The lichen genus Collema with special reference to the extra-European species. Symbolae Bot. Upsaliensis 20: 1-215.

This characteristic lichen differs from the other varieties of C. tenax, first and foremost, in the elongated and narrow lobules which are often entirely or in part raised on edge (lamellate), towards ends +/-  fan-shaped, rather sparsely but coarsely (and +/- longitudinally) rugose or plicate.—Thallus rounded, up to at least 3 cm diam., adnate, olive-green to brownish or blackish, smooth or somewhat granulose or knotty; lobes up to c. 15 mm long, repeatedly furcated or more irregularly branched, with +/- discrete lobules which are usually 0.2-1 mm broad (narrower ones like fine strings; end lobules up to c. 2 mm broad).  Thallus c. 200-300 µ thick when moist; hyphae 1-4.5 µ thick; Nostoc-cells 2-4.5 (6) µ, gelatin I+ or I-.

Apothecia occurring in some collections (see below, not in the type material), numerous to sparse, superficial or marginal, immersed to appressed or somewhat sessile, 0.6-1.2 mm diam. (rarely more, in Spanish specimens up to 2.7 mm).  Discus plane or convex or (sometimes strongly) concave, usually dark red to blackish, matt or a little glossy, epruinose.  Margo thallinus thin to moderately thick, +/- smooth and entire (sometimes a little crenulate), prominent or not so, persistent or (especially in convex apoth.) disappearing.—Apoth. studied 190-225 µ thick when moist (central part).  Excipulum thallinum without pseudocortex.  Excipulum proprium thin, euthyplectenchymatous (or in part subparaplectenchymatous).  Subhymenium c. 30 µ thick, pale brown or yellowish brown, I+.  Hymenium 65-80 µ high (in Spanish specimens 110-130 µ), I+.  Paraphyses simple or (especially in uppermost part) branched, 1.5-2 µ thick (KOH), apices up to 4.5 µ (globose or clavate).  Asci 45-50 X 8.5-13 µ (American specimens), clavate to subcylindrical.  Spores +/- oblong, 4-celled, sometimes a little constricted at septa, (17) 20-26 X 6.5 µ [in Spanish specimens (20) 26-30 (32) X 6.5 µ].

Seems to be a rare lichen, occurring on naked soil (calcareous or non-calcareous) or decaying plants at high altitudes.  It is known to me from Spain, China, and the U.S.A. (Rocky Mts. of Montana and Colorado, up to c. 3700 m), altogether nine localities.  See further below.