3. Meiotrichum (G. L. Smith) G. L. Smith, Bryologist. 95: 271. 1992.
[Greek meio-, fewer, and trichos, hair, alluding to calyptra]
Gary L. Smith Merrill
Polytrichastrum sect. Meiotrichum G. L. Smith, Mem. New York Bot. Gard. 21(3): 40. 1971
Plants robust, polytrichoid. Stems simple to freely branched. Leaves with a sheathing base and divergent blade; sheath entire, hyaline margined; limb firm, serrate-toothed to the sheath, broadly lamellate on the adaxial surface; lamellae entire in profile, the marginal cells with the free wall thickened, the cuticle longitudinally striate and pitted. Capsule ventricose, 4-6-angled; hypophysis rugose, with conspicuous stomata; exothecial cells with rounded to slit-like thin spots in the external wall; operculum hemispherical, with a stout, hooked beak; peristome present, leiodont, teeth 64, simple. Calyptra sparsely hairy. Spores papillose.
Species 1: w North America.
Meiotrichum was originally placed in Polytrichadelphus (Müller Hal.) Mitten (not present in our area) because of the fastigiate habit and sparsely hairy calyptra. All Polytrichadelphus species have lamellae which are crenulate in profile, the marginal cells smooth and flask-shaped in section, a dorsiventral capsule with two sharp angles, and multiple stomata dispersed over the exothecium, none of which occurs in Meiotrichum.