Calymperopsis involuta P.-J. Lin, Acta Phytotax. Sin. 17(1): 92. 1979. Type. China: Hainan, P. C. Chen et al. 518c (holotype IBSC). Paratypes. China: Hainan, P. C. Chen et al. 497b (IBSC); Yunnan, Xi-shuang-ban-na, W.-X. Xu 6166 (YUKU).

Plants small, ca. 1 cm high, green to blackish, solitary, loosely gregarious, or in tufts of a few plants. Stems short, rhizoids reddish brown, scanty. Leaves often dimorphic, involute and falcate when dry, mostly folded and spreading when wet, curved, vegetative leaves narrowly lance-acuminate, grading into the deltoid and often comose gemmiferous leaves, mostly 3–4 mm long, axillary hairs inconspicuous; cells of upper laminae pellucid, isodiametric to short-rectangular, smooth to sharply unipapillose abaxially, bulging adaxially; margins of upper laminae narrowly bordered entirely or in part with hyaline cells, border sometimes more or less lacking or only in traces here and there, entire or irregularly with small, remote denticulation, margins of lower laminae entire, with or without border of hyaline cells; cancellinae ending in narrow acute angles distally. Gemmae common, filamentous, borne adaxially along costa at midleaf, gemmiferous leaves narrow, similar to vegetative leaves or short, broad, deltoid, and forming comae at stem tips. Sporophytes not seen.

Type. Jamaica: Swartz s.n. (isotypes BM, NY).

Chinese specimens examined: HAINAN: Chang-jiang Co., Reese et al. 17608 (IBSC, LAF); Le-dong Co., Reese et al. 17783 (IBSC, LAF, MO). YUNNAN: Jing-hong Co., Redfearn et al. 34272 (LAF, MO); Meng-hai Co., Redfearn et al. 34102 (LAF, MO).

Habitat: evidently infrequent but easily overlooked; solitary, tufted, or in small thin colonies on tree trunks, twigs, and branches, often along streams, often high up in trees, in more or less open forests at medium elevations; Distribution: pantropical.

Syrrhopodon parasiticus is easy to recognize by its characteristic habit and habitat, and by its pointed leaves with narrow acute cancellinae and filamentous gemmae adaxially along the costa at midleaf. Although the extent of the hyaline border and the abaxial ornamentation of the leaf cells are variable, this is a well-defined species. Even though the plants are rarely or never conspicuous in the field, they can usually be found by careful searching in appropriate habitats. Twigs and branches of trees in humid sites are especially characteristic habitats for S. parasiticus.

Illustrations: Reese & P.-J. Lin 1991 (figs. 120–128).