1. Anomobryum Schimper, Syn. Musc. Eur. cxxxviii 382. 1860. • [Greek anomos, lawless or different, and bryon, moss, alluding to somewhat hypnaceous distal laminal cells].
John R. Spence
Plants small, in thin mats or scattered, pale green to yellow-green. Stems 0.5-1.5 cm, weakly to strongly julaceous, often appearing stringlike, not or weakly branched; rhizoids few, micronemata and macronemata absent or present in clusters on proximal stem. Leaves imbricate when dry, erect when moist, broadly ovate or ovate-lanceolate, flat to concave, 0.6-1.4 mm; base not decurrent; margins recurved proximally, plane distally, or often plane throughout, entire, 1-stratose, limbidium absent; apex broadly acute; costa not reaching apex or very short-excurrent, mucro smooth, guide cells absent; alar cells not differentiated from juxtacostal cells; laminal areolation distinctly heterogeneous; proximal laminal cells quadrate or short-rectangular, 1-2:1; medial and distal cells elongate-rhomboidal to elongate-vermicular, 6-10:1, walls thick, not pitted. Specialized asexual reproduction by leaf axil bulbils or absent. Sexual condition dioicous; perigonia and perichaetia terminal, leaves same size as vegetative leaves or usually larger, not forming rosette, inner leaves little differentiated. Seta single, flexuose. Capsule inclined to erect, ovate-cylindric or ovate-pyriform, 1-3 mm; hypophysis somewhat differentiated; operculum weakly convex, short-conic, not rostrate; peristome double, single, or rarely absent; exostome pale brown basally, hyaline distally, teeth slender lanceolate; endostome separate from exostome or sometimes adherent or absent, basal membrane low to high, segments present or absent, broadly perforate, cilia present or sometimes absent. Spores shed singly, 8-15 µm, finely papillose, pale tan or yellow-tan.
Species ca. 30 (2 in the flora): nearly worldwide.
Species of Anomobryum are distributed in temperate to alpine regions of the world, with concentrations in the mountains of Mexico and Central and South America. Although the genus is morphologically similar to Bryum, molecular studies consistently show that the types of the two genera, A. julaceum and B. argenteum, are not closely related. Anomobryum can generally be distinguished from Bryum by the elongate, very slender stems, suggestive of pieces of string, and extremely long distal laminal cells. Bryum species tend to have thicker, more rounded stems that are relatively short, and for the most part shorter distal laminal cells. Plants of Anomobryum have brown to orange stems. The leaf apices are not hyaline; the distal laminal cells do not occur in rows oblique to the costa; the exostome teeth are trabeculate and without pores; and the spores do not germinate in the capsule.
SELECTED REFERENCE Shaw, A. J. and A. J. Fife. 1984. The evolutionary and taxonomic significance of peristome morphology in Anomobryum (Bryaceae, Musci). J. Hattori Bot. Lab. 57: 285-298.