Plants small, 5–8 mm high, light-green, loosely gregarious or in turfs. Stems elongate, simple or forked; rhizoids dark-red, conspicuous. Leaves involute, erect-ascending and loosely secund when dry, straight and with involute margins when wet, narrowly linear to lanceolate above broader base, to 2.0–4.5 mm long, axillary hairs inconspicuous; costa smooth to papillose or remotely spinose abaxially, smooth to thickly spinose adaxially; cells of upper laminae pellucid, isodiametric to rectangular, smooth abaxially except toward margin where usually some laminal cells are papillose-spinose in abaxial intramarginal rows, but abaxial rows of spinose papillae are lacking on some leaves; margins of upper laminae narrowly bordered nearly all around with hyaline cells, border weak or lacking near leaf tip, often difficult to see in narrow leaves because of involution of leaf margins; margins of lower laminae with delicate hyaline cilia, the cilia to 70–90 µm long; cancellinae ending in acute angles distally. Gemmae inconspicuous, on adaxial surface of costa tip. Sporophytes unknown.

Type. China: Hong Kong, New Territories, Sheung Wo Hang Fung Shui Wood, L. Zhang 1079 (holotype IBSC; isotypes HKU, KFBG, LAF).

Chinese specimen examined: see the type information cited above.

Habitat: rare, on tree trunks and soil over rock in forests; alt. 130–160 m; Distribution: endemic to China.

Syrrhopodon hongkongensis is generally very similar to and closely related to S. chenii but differs in the more densely spinose costa and longer marginal cilia on the lower laminae. It is certain that numerous further collections of these two rare taxa will reveal interesting aspects of their taxonomic relationships. Several collections of this species are known in addition to the type material cited above (L. Zhang et al. 1999).

Illustrations: L. Zhang, Corlett & Chau 1999 (figs. 1–12).