Riccardia martinii Reeb & Gradst. sp. nov. (Fig. 4 A-I) DIAGNOSIS. — Dry thallus with white margins and with an orange-colored network of thick-walled dorsal epidermis cells. TYPE. — Madagascar. Alaotra-Mangoro, Zahamena Nat. Park, 17°38’22”S, 48°38’47”E 1247 m, 26.XII.2013, Reeb & Andriamanantena CR 13 Z 9* (holo-, PC [PC 0763851]). FURTHER SPECIMENS EXAMINED. — Réunion. St Denis, 1500 m, 11.X.1962. Een R 039 (S-B12531); Piton de la Fournaise, 21°19’00”S, 55°42’00”E, 800-870 m, 23.II.1995, Pócs 9501 H * (G 00264150, EGR), 21°18.5’S, 55°42’E, 800-1080 m, Pócs 9602/ CU * (G 00264153, EGR), 21°18’0S, 55°42.7’E, 1800 m, 30. VI.1996, Pócs 9612/ CC, 9 613/ CC *, 9613/CW (EGR); Plaine des Caffres, 21°09’S, 55°33’E, 1850 m, 22.VII.1996, Vojko 9660 / CS (G 00264121, EGR); Forêt de Bélouve, 21°4’S, 55°31.6’E, 1610-2000 m, Pócs 9618/ CU (EGR). Madagascar. Alaotra-Mangoro, Zahamena Nat. Park, 17°38’22”S, 48°38’47”E 1247 m, 26.XII.2013, Reeb & Andriamanantena CR 13 Z 9 * (PC 0763856), CR 13 Z 25 * (PC 0763863); Vohimana Reserve, 18°55’43.6”S, 48°29’56.6”E, 849 m, 15.IV.2010, Reeb, Andriamanantena & Bidault; CRAE 106 (PC); Sava, Marojejy Nat. Park, X.2010, Bardat JBMAD 78* (PC 0763890). Tanzania. Uluguru Mts., Kinole Village, 1480-1530 m, 05.II.1973, Pócs & Lubgwecha 6877/ K (G 00264154, EGR), Kibale Forest, 1730 m, 19.X.1971, Pócs 6477/ M (G 00264161, EGR)., Bondwa, 2125 m, 13.XII.1972, Pócs & Crosby 6947/ K (EGR), ridge and Lupanga peak, 2100-2400 m, 21.XI.1969, Pócs & Csontos 6072/ BA (EGR). DISTRIBUTION. — Tanzania, Madagascar and Réunion. HABITAT. — On dead wood, bark on peaty soils covered a dense bryophyte layer, occurring between 400 and 4000 m but mainly found at mid elevations (800-1500 m). ETYMOLOGY. — Dedicated to Martin Reeb-Leurent, born 25/05/2011. DESCRIPTION. Monoicous (autoicous) or dioicous. Thallus Fleshy to leathery,rigid, green, glossy,green to dark brown or black in herbarium, to 22 mm long, when dry crisped or with recurved branches and with white margins, main axis closely attached to the substrate or to other thalli, 1-3-pinnate, sometimes palmate in young thalli, reiterations and stolons frequently present. Main axis Irregularly defined, 400-500 µm wide, with mycorrhiza-like fungi on the ventral side (cross section), in cross section ellipsoid to biconvex, rarely plano-convex, 7-10(-11) cells thick, with ventral subepidermis, margin acute with one bulging cell, not winged, epidermis cells more than 4-5× smaller than inner cells, radial walls of the dorsal epidermis cells usually thickened and orange-colored in dry material. Primary branches 4-12 mm long. Ultimate branches Oblong, stocky to tongue-shaped, margins white or clearer, (0.2-) 1.5-3 mm long, 0.3-0.4-0.7(-1.0) mm wide, in cross section lunate to concavo-convex, 4-7 cells thick, margins acute or with a 1-2 cells wide wing, epidermis cells equal or 2-4× smaller than inner cells, branch apex emarginate, dissected or retuse, without overlapping edges, young thalli with numerous multi-apical areas. Mucilage papillae Present, apical and in two ventral rows, 70(-100) µm long, exceeding the apex. Male branches Solitary or often grouped, sessile to or stalked, sometimes prolonged by vegetative growth, curved and reflexed with age, to 1 mm long, narrowly winged. the wing narrower than the axis, margins crenate by larger cells, antheridia in up to 20 pairs. Female branches Very short when young (seemingly immersed in the vegetative tissue), ventrally to ventro-laterally inserted, narrowly winged, the wing ornamented by short, straight cilia. Calyptra Rugose by scattered thick-walled, bulging cells. Gemmae Occasionally present.

Published as part of Reeb, Catherine & Gradstein, Robbert, 2020, A taxonomic revision of Aneuraceae (Marchantiophyta) from eastern Africa with an interactive identification key, pp. 11-34 in Cryptogamie, Bryologie 20 (2) on pages 26-28, DOI: 10.5252/cryptogamie-bryologie2020v41a2, http://zenodo.org/record/12215441