Riccia stenophylla Spruce

Athira, S. & Daniels, A. E. D., 2022, Riccia stenophylla Spruce (Ricciaceae: Marchantiophyta) - a new report for Asia from the Western Ghats of India, Phytotaxa 568 (3), pp. 277-282 : 279

Riccia stenophylla Spruce , Bull. Soc. Bot. France 36(suppl. Congrès Bot. 1889): CXCV [195].1890.

- Holotype: Paraguay, Asunción, Balansa 3706 ( PC) . ( Figure 2 )

Riccia oerstediana Lindenb. & Hampe in Hampe, Linnaea 24: 304. 1851.

Riccia hosseusii Herzog, Feddes Repert. Nov. Spec. Regni Veg. 55: 5. 1952.

Plants monoicous, in overlapping patches, spongy, pale green to yellow-green. Thallus 5–8 × 1–2.5 mm, 1–3-times dichotomously branched, hyaline or translucent towards margin; segments divergent, linear, broadly acute to truncate at apex; dorsal groove distinct at apex broadening towards base; ventral scales semilunar, as broad as thallus, conspicuous towards apex of thallus; rhizoids dense, mostly tuberculate. Thallus 3–5-times as broad as high in cross section, oblongovate; air pore ca 48 × 42 µm, surrounded by a ring of 5 concentric cells; air chambers large; epidermal cells 22–35 × 20–30 µm, barrel-shaped in dorsal view, hyaline. Antheridial necks along median groove, ca 192 × 60 µm from the dorsal surface. Sporogonium along mid-dorsal line, of segments and main thallus, sunken, protruding ventrally. Spores ovoid-tetrahedral, 90–108 × 60–90 × 90–102 µm, with 6 or 7 areolae on the distal face, winged, reddish-brown to dark brown; areolae ridged, 12–25 × 18–25 µm; wings translucent, pale yellowish-orange; proximal face with ridged areolae; areolae 6–10 × 6–25 µm; triradiate mark distinct, reaching wing.

Habitat: Terricolous, near water sources in mixed plantations, ca 1000 m.

Distribution: North and South America and India: Western Ghats.

Specimens examined: India, Western Ghats, Kerala, Idukki District , 66 th Mile , ca 1000 m, 22.3.2022, S. Athira 174, 176 (SCCN) .

Figures

FIGURE 2A–J. Riccia stenophylla Spruce.A. Plants in situ. B. Thallus with sporogonia (ventral view). C. Tuberculate rhizoids. D. Airpore. E. Ventral scale. F. Antheridial neck. G. Cross section of thallus. H. Distal face of spore. I. Proximal face of spore. J. Spore: Equatorial view (from S. Athira 176).