Caribaeohypnum

• Authority

  Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part Two: Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69 (2)

• Family

  Hypnaceae

• Scientific Name

  Caribaeohypnum

• Description

  Genus Description - Plants robust, somewhat shiny, yellow-green to yellow-brown or dark red-brown. Stems creeping, up to 12 cm long, red-brown, in section oval, with a weak central strand and a cortex of about 5 layers of irregularly thick-walled cells (not hyalodermatous), rather loosely plumose-pinnate or partly bipinnate; branches spreading, sometimes tapered and occasionally flagelliform-tipped, ± curved, up to 2 cm long or rarely longer; pseudoparaphyllia very large, lanceolate. Stem leaves usually strongly falcate-secund, strongly plicate, 1.7-2.5 x 0.7-1 (-1.3) mm, ovate-lanceolate, gradually narrowed to a blunt, channeled acumen, subcordate or auriculate at base; margins plane, sermlate all around; costae distinct, separate at the base and parallel, up to 1/3 the leaf length; median cells linear, thick-walled, with lumina 50-70 x 2-4 p m , smooth; basal cells sometimes yellowish, with alar cells shorter and wider, homogeneously oblong, thick-walled, and porose, with 8-10 along the margins and forming excavate, sometimes brownish groups. Branch leaves smaller (1.1-1.8 x 0.4-0.7 mm), oblong-lanceolate with upper median cells 40-60 x 3-4 µm and alar cells less differentiated. Dioicous. Perichaetial leaves long-lanceolate, gradually tapered to a very long, subentire acumen, smooth or slightly plicate; costae weak or indistinct. Setae 3-4 cm long, smooth, yellow- to red-brown, curved but scarcely twisted when dry; capsules suberect to inclined, 2.5-4 mm long, 0.9-1.2 mm broad, long-cylindric, weakly curved; annulus slightly differentiated; operculum conic-apiculate; exothecial cells subquadrate below the mouth, larger, rectangular, and shghtiy collenchymatous below; exostome teeth subulate-lanceolate, gradually tapered, pale-yellow, densely papillose throughout but transversely papillose-striolate on the outer surface below, scarcely bordered; with rather low but projecting trabeculae at back; endostome considerably reduced, pale-yellow, densely papillose, with a fairly low basal membrane, narrow, shghtiy keeled, non-perforate segments, and cilia mdimentary or none. Spores 26-35 µm, roughly papillose.

• Discussion

  The genus is characterized by strongly plicate leaves with stout, parallel costae (about one-third the leaf length) and excavate alar groups consisting of homogeneous cells with thick, porose walls; suberect cylindric capsules with subcollenchymatous exothecial cells; densely papillose exostome teeth (with transversely papillose striae below); and reduced endostomes. It consists of a single species.