2. Andreaea mutabilis Hook. f & Wils., London J. Bot. 3: 536. 1844.
Andreaea hohuanensis Chuang, J. Hattori Bot. Lab. 37: 427. 1973. Type. China: Taiwan, C.-C. Chuang 5914 (holotype UBC). Synonymized by Murray (1988).
Plants small, slender, ca. 1 cm high, purple-red to black, in dense tufts. Stems rigid, erect, moderately branched. Leaves 0.60–0.75 mm × 0.1–0.2 mm, erect to erect-spreading when dry, often distant, sometimes falcate-secund, lanceolate, with long acuminate to acute apex; the lower leaves small, with broader base and shortly acute apex; margins entire, more or less incurved; upper and median laminal cells irregularly round to oval, 4–8 µm × 3–6 µm, thick-walled, papillose; basal cells near margins isodiametric to oblate, 4–8 µm × 8–10 µm; central basal cells elongate, 20–30 µm × 4–5 µm, irregularly thick-walled, pitted. Autoicous. Perichaetial leaves oblong-lingulate, acuminate, about 1 mm long. Pseudopodium ca. 1 mm long. Capsules oblong-ovate, dark brown, 0.5–0.6 mm long, split from near base to apex into 4 valves when mature. Spores 14–18(–20) µm in diameter, finely papillose.
Type. New Zealand, Auckland Island, J. D. Hooker 50 (lectotype BM); Campbell Island, J. D. Hooker Ib. (syntype BM).
Chinese specimen examined: TAIWAN: Ping-tung Co., C.-C. Chuang 1510 (UBC). Also see the type information of A. hohuanensis cited above.
Habitat: on open, dry rocks in high mountains, 2190–3200 m; Distribution: China (Taiwan), Kalimantan, Sulawesi, New Guinea, Australia, Tasmania, New Zealand, Europe, and North and South America.
Andreaea mutabilis is easily recognized by the differentiation of its isodiametric basal marginal cells in contrast with the elongate, pitted, centrally located basal cells. The narrowly acuminate leaves with a long lanceolate upper part are different from those of A. rupestris. Another diagnostic feature of A. mutabilis is that its capsules split longitudinally from the base to the apex.
Illustration: C. Gao (ed.) 1994 (Pl. 24, figs. 1–19); T. Cao & C. Gao 1995 (Fig. 2, A–P).