Aloina bifrons

Detailed description

Minute, loosely tufted moss forming diffuse patches on limestone rock. Stems thick, up to 2 mm tall, stout, comose. Leaves c.2 mm long, imbricated and incurved when dry, spreading when moist, thick, fleshy more or less succulent; lamina broadly elliptic, base sheathing, distinctly concave, margins widely involute from close to base, hooded and subacute at apex. Nerve very broad, flat and indistinct, excurrent, finely cuspidate in the lower leaves, and as a long, smooth, hyaline arista in the upper ones. Ventral surface of the nerve and lamina, excluding the involute margins and the short base, entirely covered by a dense mat of filaments which conceal the areolation in that part of the ventral surface of the lamina. Upper cells c.15 microns, subisodiametrical, irregularly angled, smooth, strongly incrassate, narrowly transversely elliptic towards the margin. Cells below larger, subquadrate, pellucid, with thinner walls which are sometimes collenchymatously thickened at the angles. Marginal cells below somewhat transversely lengthened. Seta to 14 mm long, flexuose. Capsule 3.0-3.5 mm long, brown, erect, cylindrical, with the base slightly broadened. Peristome teeth 32, arising from a low basal cylinder. spirally twisted to the left. Operculum narrowly conical, suberect, about 1/3 the length of the capsule.