Monographs Details: Calyptothecium
Authority: Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
Description:Genus Description - Plants mostly robust, rarely somewhat smaller, in green to golden, thin to dense, epiphytic colonies. Primary stems creeping, filiform, with small, reduced leaves, turning ca. 90° and becoming the upright secondary stem (stipe), the creeping stem continuing by a bud from near the base of the stipe, secondary stems erect to pendent, usually pinnately branched, rarely simple, rarely becoming flagellate, complanate-foliate; in cross-section with small thick-walled cells surrounding larger firm-walled cells, central strand none; paraphyllia none; pseudoparaphyllia filamentous, numerous; axillary hairs with a single short brown basal cell and ca. 3 elongate hyaline distal cells. Secondary stem and branch leaves somewhat differentiated, the stem leaves larger and more strongly auriculate; branch leaves not in conspicuous rows, imbricate, little altered when dry, spreading, oblong-ovate, acute to short-acuminate, deeply concave, often rugose, auriculate; margins entire to serrulate above, plane; costa mostly single and ending near midleaf, rarely absent; cells linear, smooth or prorulose, often thick-walled and porose; alar cells not in a distinct group but shorter and colored along the insertion. Asexual propagula of gemmae often clustered in leaf axils, uniseriate. Mostly dioicous, rarely autoicous. Perichaetia conspicuous; leaves strongly differentiated, erect, convolute, lanceolate, acuminate; margins entire throughout or serrulate above, plane; costa single or absent; cells elongate, smooth, thick-walled, porose. Setae mostly very short, rarely elongate, smooth; capsules immersed or rarely exserted, erect and symmetric, short-cylindric; exothecial cells short-rectangular, firm-walled, becoming oblate at the mouth; annulus not differentiated; operculum conic-rostrate; peristome double or apparently rarely with endostome absent, inserted slightly below the mouth, yellow, exostome teeth often irregular and perforate, most unornamented, often with a well-developed prostome; endostome, when present, with a low basal membrane, segments linear, cilia absent. Spores spherical, finely papillose, relatively large. Calyptrae mitrate or, reportedly, cucullate, small and only covering the operculum, naked or sparsely hairy.
Discussion:Calyptothecium Mitt., J. Linn. Soc., Bot. 10: 190. 1868; Pterobryon sect. Calyptothecium (Mitt.) Mitt., J. Linn. Soc., Bot. 12: 427. 1869; Pterobryon subgen. Calyptothecium (Mitt.) Mitt., Trans. Roy. Soc. Victoria 19: 81. 1882.
Pterobryopsis sect. Pseudo-Calyptothecium Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 802. 19 Apr 1906; Calyptothecium sect. Pseudo-Pterobryopsis M. Fleisch., Musci Buitenzorg 3: 859. 1908, nom. illeg.; Calyptothecium sect. Pseudo-Calyptothecium (Broth.) Wijk & Margad., Taxon 8: 72. 1959.
Calyptothecium sect. Pseudo-Neckera Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 839. 31 Jul 1906, nom. illeg. incl. typ. sp.
Discussion. Calyptothecium is recognized by its erect to pendent secondary stems that are pinnately branched and frondose with complanate foliation. The leaves are often somewhat to strongly auriculate. The costa is usually single and the leaf cells mostly thick-walled and porose. The genus is weakly segregated from Jaegerina. It primarily differs by the more branched stems, complánate foliation, and auriculate leaves. Argent’s (1973: 563-602) treatment of the African taxa may be consulted for his generic concept of Calyptothecium but in our flora there should be no problem in recognition since our only species is distinctly complanate-foliate.