Plagiochila punctata (Taylor) Taylor var. punctata

Gradstein, S. Robbert & Reeb, Catherine, 2022, The genus Plagiochila (Dumort.) Dumort. (Marchantiophyta) in Madagascar, Cryptogamie, Bryologie 20 (5), pp. 65-106 : 88

Plagiochila punctata (Taylor) Taylor var. punctata ( Vanden Berghen 1981: 56, fig. as P. subalpina )

Jungermannia punctata Taylor, Transactions of the Botanical Society of Edinburgh 1: 179 (1844). — Plagiochila punctata (Taylor) Taylor, London Journal of Botany 5: 261 (1846). — Type: Ireland. Unknown collector (FH?; fide Heinrichs et al. 2005b).

Plagiochila subalpina Steph. , Hedwigia 30: 268 (1891), nom. illeg. — Type: Tanzania ( Heinrichs et al. 2005b).

SPECIMENS EXAMINED. — Madagascar. Prov. Fianarantsoa • Ranomafana Nat. Park, E. ridge of Mt. Vohipanani , 1140-1230 m, VII.2003, Pócs & Ranaivojaona 04121/ CU ( EGR) .

Additionally reported from Ambohimahasoa (Onraedt 70M532), c. 100 km N of the town of Fianarantsoa by Vanden Berghen (1981).

DISTRIBUTION AND HABITAT. — Afro-American: tropical America, Bioko, East Africa; also in western Europe. In Madagascar rare, found on bark, rock and soil in subhumid evergreen forests above 1000 m, in rather exposed environments.

DESCRIPTION (see also Vanden Berghen 1981; Fischer 2013, both as P. subalpina )

Plants very small, 0.5-1.5(-2) mm wide, c. 1-1.5 cm long, green to greenish-brown, becoming blackish-brown when dry, sparsely branched, branches intercalary, frequently denuded or flagelliform due to copious production of caducous leaves, rhizome-like shoot absent. Mature stem leaves distant to subimbricate, rather widely spreading, ventrad, obovate-suborbicular, 1-1.3× longer than wide, not ampliate, unbordered, apex rounded, margins plane, with 3-6 long, narrowly triangular teeth at the apex and on the upper half of the ventral margin, teeth made up of short cells, apex frequently bifid (to 1/3) or trifid by larger, lobe-like teeth; dorsal and ventral bases scarcely decurrent. Leaf cells subisodiametrical, c. 20-30 µm wide in midleaf, with small to large, swollen trigones, leaf base with a short vitta-like area of large cells; cuticle smooth; oil bodies not observed. Underleaves absent. Gametoecia not seen. Vegetative reproduction by caducous leaves, the caducous leaves similar to ordinary leaves or much smaller, deeply bifid.

NOTES

Plagiochila punctata (sect. Arrectae) is characterized by the small plants (0.5-1.5mm wide) with numerous leafless shoots due to caducous leaves. The persistent leaves are rather widely spreading, ventrad, obovate-suborbicular, 1-1.3× longer than wide, with 3-6 rather long teeth at the apex and on the upper half of the ventral margin. The remnant leaves on denuded shoots are usually minute and deeply bifid.