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Family: CollemataceaeGenus: Lathagrium
Thallus foliose, to 2.5 cm diam., often circular but sometimes forming more extensive, bright green, olive-green to brown patches; rather thin, often ascending, composed of repeatedly branched, strap-like lobes that splay out at their ends, swollen when wet. Upper surface brown-pigmented, visible in section but not in fresh fully hydrated material. Upper and lower cortex absent, attached to substratum by hapters. Isidia absent. Photobiont Nostoc, cells distributed throughout the thallus and not forming a discrete layer, though concentrated towards the upper surface.
Anamorph: conidiomata 300-550 μm diam., rather frequent, erumpent from the thallus, often similar to young urceolate apothecia, with a small ‘disc’ and a thick thalline margin, green to reddish yellow with a blackened apex, appearing as swollen low tubercles with a prominent opening. Internal tissues composed of a matrix of irregular thin-walled hyaline cells, with conidia developing within irregular locules. Conidial development not clear. Conidia 5-6.5 (-8) × 1.2-1.5 μm, cylindrical with rounded ends, often slightly curved or constricted in the central part, aseptate, hyaline, smooth, without a gelatinous sheath or appendages.
Teleomorph: ascomata apothecia, rarely numerous, superficial. Disc 0.7-1 mm diam., reddish brown, flat, with a thin, entire, smooth thalline exciple composed of thick-walled globose cells. Epithecium indistinct, mid brown. Hymenium hyaline, I+ blue. Hypothecium ± hyaline. Interascal tissue of paraphyses, branched and anastomosed especially near the apices, apices often clavate, yellowish. Asci cylindric-clavate, apex rounded and strongly thickened, apical dome I+ blue, with a downwardly projecting I+ blue annulus and apical cap, 8-spored. Ascospores arranged obliquely uniseriately to biseriately, 20-30 × 8.5-13 μm, 3-septate or submuriform, with one incomplete longitudinal septum, hyaline, thin-walled, smooth, without an epispore, gelatinous sheath or appendages.
Chemistry: no lichen products detected.