Plagiochila squamulosa Mitt.

Gradstein, S. Robbert & Reeb, Catherine, 2022, The genus Plagiochila (Dumort.) Dumort. (Marchantiophyta) in Madagascar, Cryptogamie, Bryologie 20 (5), pp. 65-106 : 94-96

Plagiochila squamulosa Mitt.

( Fig. 19 )

Plagiochila squamulosa Mitt. , Journal of the Proceedings of the Linnean Society, Botany 7: 165 (1864). — Type: Cameroun. Mt. Cameroon, Mann s.n. (holo-, BM; iso-, NY; fide Grolle 1995).

Plagiochila crispulocaudata Gottsche, Abhandlungen des Naturwissenschaftlichen Vereins zu Bremen 7: 340 (1882). — Plagiochila squamulosa var. crispulocaudata (Gottsche) Vanden Bergh. , Bulletin du Jardin botanique national de Belgique 51: 74 (1981). — Type: Madagascar ( Vanden Berghen 1981).

Plagiochila sinuosa Mitt. , Journal and Proceedings of the Linnean Society of London 22: 319 (1886). — Plagiochila squamulosa var. sinuosa (Gottsche) Vanden Bergh. , Bulletin du Jardin botanique national de Belgique 51: 74 (1981). — Type: Tanzania ( Vanden Berghen 1981). Reported from Madagascar by Stephani (1906).

B C A D F E G H

SPECIMENS EXAMINED. — Madagascar. Prov. Antananarivo • Manjakatompo Reserve, Tavolotara Forest, 2100 m, XII.2017, Reeb 17 M503 ( PC); Vakinankaratra, 1733 m, XII.2017, Reeb 7 M401 ( PC). — Prov. Fianarantsoa • Andringitra Nat. Park, near Antanifotsy, trail to Pic Boby , IX.1994, Orbán 9463/AI ( EGR) .

DISTRIBUTION AND HABITAT. — Bioko, East Africa, Madagascar, La Réunion; recorded from Madagascar byVanden Berghen (1981) without citation of material. In Madagascar found on rock in secondary grassland with ericaceous bushes, 1900-2000 m.

DESCRIPTION (see also Jones 1962 as P. crispulocaudata and P. squamulosa ; Vanden Berghen 1981) Plants 3-3.5mm wide,to 4cm long,rather rigid,irregularly pinnate, branches terminal and intercalary.Creeping,rhizome-like primary stem present.Ventral stem surface with small paraphyllia between the decurrent strips of the ventral leaf margin,the paraphyllia consisting of short rows of rounded cells.Mature stem leaves densely imbricate and ventrad, obliquely spreading, very asymmetrical, ovate-triangular, c. 1-1.5× longer than wide, strongly ampliate, margin unbordered, apex broadly rounded, ventral margin undulate in the lower half, margins subentire or with up to 8 short, 1-2 cells long teeth on the apical margin; dorsal bases longly and very broadly decurrent, entirely concealing the stem, ventral base shortly to rather longly decurrent, the decurrent slightly undulate. Leaf cells subisodiametrical, c. 18-25 µm wide in midleaf, with cordate to symmetrically swollen trigones; vitta-like area absent; cuticle smooth; oil bodies not observed. Underleaves small to large,ciliate-laciniate.Androecia terminal to intercalary, of 4-10 pairs of bracts. Perianth without stalk, perianth mouth densely toothed by shortly triangular teeth.Vegetative reproduction not observed.

NOTES

Plagiochila squamulosa (sect. Vagae) is a common and variable species in the mountains of East Africa; several varieties have been described ( Jones 1962; Vanden Berghen 1981). The species is close to P. corrugata but differs from the latter in the presence of small paraphyllia on the ventral stem surface (consisting of short rows of rounded cells) and the ventral leaf margin being undulate only in the lower half and usually toothed. The examined Madagassan material of P. squamulosa , however, stands out by leaf margins with very few teeth.

Figures

FIG. 19. ― Plagiochila squamulosa Mitt.: A, habit; B, C, shoot in ventral view; D, shoot in ventral view with some leaves removed, showing paraphyllia; E, shoot in dorsal view; F, leaves; G, underleaves; H, midleaf cells. From Reeb CR17M503 (PC, TAN). Scale bars: A, 5 mm; B-D, G, 0.25 mm; E, F, 1 mm; H, 0.05 mm.