John R. Spence

Plants small to large, in dense turfs, green, yellow-green, red-brown, pink, or red. Stems 0.5-4 cm, evenly foliate, not or rarely weakly julaceous, somewhat branched; rhizoids few (many in P. brachyneura), micronemata and macronemata absent from stems or present in clusters on proximal stem. Leaves imbricate to somewhat contorted when dry, erect to erect-spreading when moist, ovate to suborbicular, flat to concave, 0.4-3(-3.5) mm; base decurrent or not; margins plane or sometimes recurved proximally, ± entire, 1-3-stratose, limbidium absent or present; apex obtuse to acute; costa not reaching apex to very short-excurrent, apiculus smooth, guide cells absent or sometimes present proximally; alar cells not differentiated from juxtacostal cells; laminal areolation somewhat heterogeneous; proximal laminal cells usually long-rectangular, 3-5:1; medial and distal cells highly variable, irregularly rhomboidal, sometimes ± quadrate near apex, , 1-4:1, walls thin or incrassate, not pitted. Specialized asexual reproduction absent or by rhizoidal tubers . Sexual condition dioicous or rarely synoicous; perigonia and perichaetia terminal, leaves same size as vegetative leaves or usually larger, not forming rosette, inner leaves little differentiated. Seta single, straight to flexuose or twisted, rarely geniculate. Capsule inclined to suberect, elongate-pyriform, , 2-4 mm; hypophysis differentiated, often elongate; operculum conic, apiculate or not, not rostrate; peristome double; exostome pale yellow or tan proximally, hyaline distally, teeth lanceolate; endostome separate from exostome or sometimes adherent, basal membrane high, segments rarely longer than exostome, rarely absent, narrowly perforate, cilia absent or sometimes present. Spores shed singly, 11-28 µm, papillose or smooth, pale brown, tan, or yellow-tan.

Species 15 (5 in the flora): North America, Mexico, West Indies, Central America, South America, se Asia, Africa, w Pacific Islands, Australia; tropical to warm-temperate regions.

Plagiobryoides is similar to Plagiobryum in gametophyte structure, but has more or less symmetric capsules with the endostome typically shorter than the exostome, and spores that are shed singly. The two genera are probably closely related, with primary speciation of Plagiobryum in arctic-alpine regions of the Northern Hemisphere and Plagiobryoides in the Tropics. Although the genus was originally described for the highly unusual Plagiobryoides incrassatolimbata, the overall leaf structure, especially the laminal areolation, is similar to that of the other species, with typically very broad thin-walled cells, becoming very long proximally, while the capsules are also similar in overall shape. As in Plagiobryum, the endostome segments can sometimes be longer than the exostome teeth, especially in some populations of Plagiobryoides cellularis. Several species have only recently been collected in the flora area, and are quite rare. B. H. Allen (2002) provided valuable information on the Neotropical species. The leaves are usually red at the base. The leaf apices are not hyaline; the innovation leaves are smaller than the cauline leaves, with more obtuse apices and weaker costae; the setae are red-brown; the capsules are brown; and the exostome teeth are trabeculate and without pores.

Lower Taxa

• Plagiobryoides brachyneura (Kindberg) J. R. Spence
• Plagiobryoides cellularis (Hooker) J. R. Spence
• Plagiobryoides incrassatolimbata (Cardot) J. R. Spence
• Plagiobryoides renauldii (Röll ex Renauld & Cardot) J. R. Spence
• Plagiobryoides vinosula (Cardot) J. R. Spence