Plants gregarious or tufted, pale green to brownish, straight or curved at tips when dry, to 5 mm or more but mostly much shorter. Leaves dimorphic; vegetative 1-3 mm; distal lamina oblong to broadly linear-lanceolate; margins 1-stratose or slightly thickened distally, entire; costa in cross section showing ad- and abaxial bands of stereid cells; medial cells distinct, 7-8 µm, slightly bulging adaxially, smooth or minutely papillose abaxially; teniolae absent; cancellinae ending in broad angles distally, adaxial cells smooth distally; gemmiferous leaves with apex of costa excurrent, bearing gemmae in pale golfball-like spheres all around on costa apex.
11. Calymperes tenerum C. Müll. 细叶花叶藓 xi-ye hua-ye xian Linnaea 37: 174. 1872. Type. India: Bengalia, Calcutta, S. Kurz s.n. (isotype BM). Plants small, pale, compact, in low turfs. Stems short, forked; rhizoids brown. Leaves only somewhat dimorphic, 2–3 mm long, not much contorted when dry, usually secund, straight and erect-spreading when wet, vegetative leaves oblong, gemmiferous leaves oblong or acuminate, axillary hairs inconspicuous; costa excurrent in gemmiferous leaves; cells of upper laminae isodiametric, smooth to unipapillose abaxially, mammillose-papillose adaxially; margins unistratose or slightly thickened, entire throughout; teniolae lacking; cancellinae narrow, typically truncate distally. Gemmae common, in pale spherical clusters all around on tip of excurrent costa. Sporophytes not seen.
Plants small, dark green to yellow-green, scattered or in small tufts; corticolous. Stems erect, 1-2 mm high, unbranched; in section without central strand, cortical cells large, thickened, becoming smaller toward margin. Leaves incurved or contorted dry, erect-spreading wet; oblong or occasionally weakly obovate, 2.0-2.8 mm long; apex acute to obtuse; base not broader than lamina; margins plane, entire, thickened above base, in section forming small knob of 3-5 round cells. Costa short-excurrent, with gemmiferous tip, dorsally spinulose above base; in section oval, guide cells 6, ventral substereid band 5 cells thick, cells irregularly shaped, ventral surface cells slightly smaller than laminal cells, sharply mammillose, dorsal substereid band to 6 cells thick, cells irregularly shaped, dorsal surface cells round, sharply mammillose. Upper laminal cells quadrate to hexagonal, mammillose ventrally, weakly papillose dorsally; marginal cells quadrate, smooth, rectangular below; cancellinae rectangular; teniolae absent. Gemmae fusiform, in apical cluster on all sides of excurrent costa. Sporophyte not known from Africa.
C. tenerum has been collected in Java, west and east Africa, the West Indies, Mexico and southern Florida, U.S.A. The Southern African specimens were collected on trees along Ku-Nkanini Stream in northern Zululand and in coastal dune forest near Sodwana Bay.