Cyrto-hypnum scabrosulum (Mitt.) W.R.Buck & H.A.Crum

Authority

Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.

Family

Thuidiaceae

Scientific Name

Cyrto-hypnum scabrosulum (Mitt.) W.R.Buck & H.A.Crum

Description

Species Description - Plants small and slender, in typically stiff, dull, mostly green to yellow-green, often lax mats. Stems creeping, to ca. 6 cm long, regularly 2-pinnate, not frondose; in cross-section with 4-5 rows of small thick-walled cells surrounding larger thinner-walled cells, central strand small, of small cells; paraphyllia moderately abundant on stems, sparse at base of primary branches, none on secondary branches and distal ends of primary branches, filamentous, uniseriate, unbranched, 2-5 cells long, the cells quadrate, ca. 1:1, all cells pluripapillose, the distal cell truncate; pseudoparaphyllia foliose, the margins regularly serrulate, cells pluripapillose; axillary hairs usually with a single short-rectangular brown basal cell and a single elongate hyaline distal cell. Stem and branch leaves strongly differentiated, stem leaves appressed when dry, erect-spreading when moist, broadly ovate-triangular, 0.3-0.6 mm long, ± abruptly broadly acuminate, concave, not plicate, short-decurrent; margins crenulate-papillose throughout, narrowly recurved below; costa single, broad, ending in but not filling the acumen; cells short-rectangular, pluripapillose with 2-5 papillae/ cell on both surfaces, the papillae arranged around the periphery of the lumina, firm-walled, becoming longer in the acumen and juxtacostally; alar cells not differentiated but cells quadrate in large areas in basal angles. Secondary branch leaves incurved when dry, spreading when moist, laxly disposed so that branches obviously exposed when dry, ovate, 0.15-0.24 mm long, obtuse to broadly acute, concave, not plicate, subauriculate; margins regularly crenulate-papillose, plane; costa single, ending ca. 2/3 the leaf length, apical portion often covered with quadrate cells, not or scarcely projecting at back; cells ± quadrate, pluripapillose on both surfaces, the papillae arranged around the periphery of the lumina, thin-walled, ca. 6 µm wide; alar cells not differentiated. Asexual propagula none. Autoicous. Perichaetia conspicuous; leaves erect-spreading, lanceolate, ca. 1 mm long, subulate-acuminate; margins mostly subentire to crenulate throughout, occasionally with a few short straight cilia, plane; costa single, broad, extending into and filling almost all the acumen; cells rectangular to long-hexagonal, ca. 3:1, smooth, thin-walled. Setae elongate, slender, roughened throughout, orange, 0.7-2 cm long; capsules horizontal to pendent, short-cylindric, 0.5-1 mm long; exothecial cells quadrate to short-rectangular, thin-walled; annulus of 1-2 (-3) rows of small, rectangular, firm-walled cells; operculum obliquely long-rostrate, longer than or almost as long as the urn; exostome teeth yellow to yellow-brown, shouldered, bordered, on the front surface cross-striolate below, becoming papillose and then coarsely papillose above, trabeculate at back; endostome mostly with a high, smooth to finely and sparsely papillose basal membrane, segments papillose, keeled, narrowly perforate, ca. as long as the teeth, cilia papillose, in groups of 1-2 (in the same endostome). Spores spherical, finely papillose, 14-18 µm diam. Calyptrae cucullate, naked, smooth.

Discussion

4. Cyrto-hypnum scabrosulum (Mitt.) W. R. Buck & H. A. Crum, Contr. Univ. Michigan Herb. 17: 67. 1990; Thuidium scabrosulum Mitt., J. Linn. Soc., Bot. 12: 574. 1869. Plate 76, figures 1-11 Thuidium complanum Mitt., J. Linn. Soc., Bot. 12: 575. 1869. Discussion. Cyrto-hypnun scabrosulum is characterized by incurved, laxly spaced secondary branch leaves that, when dry, allow the branches to be visible. The perichaetial leaves have a costa that fills almost the whole length of the acumen, and the margins are not ciliate or have only a few, erect cilia. The species has been confused with C. schistocalyx. In fact, the two may only be forms of a single species. However, at least in the West Indies, there is seldom any confusion. Thuidium ciliatum Mitt., of Amazonian Peru, is probably a form of C. scabrosulum. Although the perichaetial leaves are somewhat ciliate, the cilia are few and erect. The costa of the inner perichaetial leaves fills the acumen as in C. scabrosulum rather than ending at its base as in C. schistocalyx.

Distribution

Range. Southern Central America, northern lowland South America, Trinidad; Cuba, Hispaniola (Haiti and Dominican Republic), Puerto Rico, St. Lucia; growing over limestone and old wood, in mostly mesic to humid lowland forests, to ca. 300 m.

Nicaragua Central America| Costa Rica South America| Panama Central America| Colombia South America| Venezuela South America| Trinidad and Tobago South America| Haiti South America| Dominican Republic South America| Puerto Rico South America| Saint Lucia South America|