Plants tiny, 3–5 mm high, yellowish green, in loose tufts. Stems elongate, forked; rhizoids dark-violet, 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 4–5 mm long, axillary hairs inconspicuous; costa smooth or remotely spinose abaxially, remotely 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 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 30–60 µm long; cancellinae ending in acute angles distally. Gemmae scanty, inconspicuous, on adaxial surface of costa tip. Sporophytes unknown.

Type. China: Guangdong, Zhao-qing Co., Ding-hu Shan (Mt.) Nature Preserve, 23°8'N, 112°35'E, 240–300 m, Redfearn et al. 34406 (holotype PE; isotypes H, HIRO, IBSC, LAF, MO, NY); Redfearn et al. 34412 (paratypes H, IBSC, LAF, MO, NY, PE).

Chinese specimens examined: GUANGDONG: Zhao-qing Co., Ding Hu Shan (Mt.), P.-J. Lin 4413 (IBSC, LAF), Magill 8097A (MO). GUANGXI: Shang-si Co., P.-J. Lin et al. 1828 (IBSC, LAF).

Habitat: rare on tree trunks and bases, palm and tree fern stems, and decaying logs in forests at low elevations; 240–610 m; Distribution: endemic to China.

At the time S. chenii was described it was known from only two specimens, but additional specimens have since been discovered. This species is distinct from all other Syrrhopodon species, except S. hongkongensis, by its remarkable intramarginal rows of spinose papillae on the leaves, with the leaf cells otherwise smooth abaxially. Although S. chenii may be superficially similar to S. spiculosus, that species has its leaf cells strongly abaxially papillose, among other differences. In some specimens of S. chenii the leaves are mostly broad; in other specimens, such as P.-J. Lin 4413 (IBSC, LAF), many leaves are very narrow and quite different in aspect from the broad leaves. See comments under the very similar S. hongkongensis for differentiation from that species.

Illustrations: Pl. 95, figs. 1–6.