3. Groutiella Steere, Bryologist. 53: 145. 1950. • [For Abel Joel Grout, 1867-1947, American bryologist].
Micromitrium Schimper ex Bescherelle, Mém. Soc. Natl. Sci. Nat. Cherbourg 16: 190. 1872, not Austin 1870
Plants small, in tomentose mats. Stems creeping, branches erect. Leaves contorted and spirally twisted around stem, ± undulate when dry, erect to wide-spreading when moist, lanceolate to lingulate, sometimes rugose; margins entire or denticulate; apex rounded-obtuse and mucronate or acute and subulate; costa percurrent or excurrent; basal laminal cells oblate to rounded; distal cells rounded-hexagonal or irregularly rounded to elliptic-hexagonal, 3-9 µm, smooth; marginal cells distinct from basal. Sexual condition dioicous or pseudautoicous; perichaetial leaves similar to stem leaves. Seta to 11 mm. Capsule exserted, oblong-ovate to cylindric, usually smooth or obscurely plicate when old, not constricted below mouth; stomata superficial; peristome rudimentary; exostome absent; endostome basal membrane usually low, papillose. Calyptra mitrate, conic, ± lacerate, or divided into many lobes, smooth, naked, plicate, covering less than 1/2 capsule. Spores isosporous or anisosporous.
Species ca. 20 (2 in the flora): Florida, Mexico, Central America, South America, Asia, Africa, Australia; pantropical regions.
In Groutiella, the branches are usually simple, to 2 cm; the leaf margins are plane or broadly reflexed; the basal laminal cells are yellowish; the distal cells are bulging; the marginal cells are elongate-linear basally, extending 1/4 or more the leaf length, sometimes nearly to the apex as a border; and the operculum is more or less convex-conic with a long rostrum.
