Macromitrium pentastichum

Macromitrium pentastichum C. Mull
Linnaea 21: 186. 1848.
Macromitrium dentatulurn C Mull. Hedwigia ^37: 237 -1898 Macromitrium hirtellum E. Bartr. Contr. U. S. Nat. Herb. 26: 86. 1928.
Plants in "rather loose, yellowish green tufts" (according to Bartram); secondary stems erect, sparingly branched, about 2 cm. high, radiculose at the base; leaves erect and flexuouscontorted when dry, flexuousspreading when moist, about 3 mm. long, oblong-lanceolate, shortly acuminate, carinate, serrulate through about the terminal half; costa short-excurrent ; upper leaf-cells rounded-quadrate to subcircular, up to 12 /z in diameter, in more or less apparent rows, hardly incrassate, mammillose on both faces, gradually elongating in the basal yi to the linear, smooth basal cells; perichaetial leaves up to 5 mm. long, linear-lanceolate, abruptly contracted to a linear, denticulate hair-point consisting mainly of the excurrent costa, the cells of the lower % elongate ; autoicous, some of the antheridial buds gemmif orm on the ventral side of the costa of the older leaves; seta 6-8 mm. long, smooth; capsules globose-pyriform, the urn not quite 2 mm. long, smooth except for the short, sulcate neck; calyptra laciniate at the base, long-pilose; operculum about 1 mm. long, abruptly rostrate; peristome double, the outer of strongly papillose teeth which are scarcely separated, the inner a papillose membrane of about the same height.
Type locality : On branches of trees in moist dark woods, Surinam {Kegel) . Distribution: Mexico; Costa Rica; British Honduras; the West Indies; South America.