Riccardia ramosissima (Steph.) Grolle

Reeb, Catherine & Gradstein, Robbert, 2020, A taxonomic revision of Aneuraceae (Marchantiophyta) from eastern Africa with an interactive identification key, Cryptogamie, Bryologie 20 (2), pp. 11-34 : 29-30

Riccardia ramosissima (Steph.) Grolle

( Fig. 4 J-O)

Aneura ramosissima Steph. , Bulletin de la Societé Royal de Botanique de Belgique 30: 196 (1891) — Type: Réunion, Rodriguez s.n. (G-00045033).

Aneura compacta Steph. , Hedwigia 32: 19 (1893). — Riccardia compacta (Steph.) S.W.Arnell, Botaniska Notiser 1952: 141 (1952). — Type: South Africa, Cape province, Jelinek s.n. (lecto-, here designated, G[G00067549]!; isolecto-, PC[PC0101714]!, S[SB20511]!) syn. nov. FURTHER SPECIMEN EXAMINED. — Ethiopia. Bale Montane, above Rira W of Aduka, 06°43’N, 39°42’E, 3320 m, 13.II.1990, Miehe 2541 (EGR).

Madagascar. Alaotra-Mangoro, Zahamena Reserve, highest part of the river above base camp, 17°38’22.7”S, 48°38’45.3”E, 1294 m, 01. I.2014, Reeb CR 13 Z 51* ( PC 0763864).

South AFrica. Mpulalanga province, Mriepskop Mt., 1550 m, 18. VI.1969, Vorster 828 B (E-00430437); Cape province, Apollo Peak, 1219 m, 31.III.1956, Esterhuysen & Arnell 4361 (PRE-0501890).

Tanzania. Mt. Kilimanjaro, 1972, Pócs 6718, 6789/ B ( EGR, G 00264060), ibid., 1984, Pócs 6981/ A ( EGR, G 00264135, G 00264136).

DISTRIBUTION. — Ethiopia, Tanzania, Uganda, South Africa, Madagascar, Réunion.

HABITAT. — On rotten wood, moist rock and humic soil in forests and along streams, between 1200 and 3800 m.

DESCRIPTION

Monoicous (autoicous) or dioicous.

Thallus

Dull or glossy yellow-green to green when fresh, dark brown to black in herbarium, leathery, rigid, growing in numerous layers, to 15 mm long, 1-2(-3)-pinnate, corymbose, not palmate, branches alternate to subopposite, reiterations frequently present in mature thalli.

Main axis usually

Ill-defined due to the densely corymbose ramification, in cross section rounded to ellipsoid at the base, 5-10 cells thick, 300-400 µm wide, in the middle ellipsoid to biconvex (rarely plano-convex), 300-500 µm wide, margins obtuse by bulging cells, not winged, epidermis cells c. 2-4 × smaller than inner cells at least on the ventral side of the axis, occasionally equal is size.

Primary branches

And reiterations to 7 mm long.

Ultimate branches

Linear to triangular, sometimes sinuous (horizontally curved), 0.5-3(-5) mm long, 0.2-0.3 mm wide, in cross section plano-convex to biconvex, 3-6 cells thick, margins with 1-3 cells wide wings, outer margins often crenate by bulging cells, epidermis cells 2-4 × smaller than inner cells, branch apex rounded to acute, emarginate to weakly dissected.

Mucilage papillae

Apical and in two ventral rows.

Oil bodies

Ellipsoid, finely granular, 2-4 per cell.

Male branches

Solitary, along the axis, shortly stalked, sometimes prolonged by vegetative growth, straight, 400-450 µm long, with a narrow, 1 cell wide wing.

Female branches

Along the axis and primary branches, laterally inserted, to 500 µm long, margin scaly and with hair-like, straight cilia, length of cilia and scales exceeding the width of the axis.

Calyptra

To 2.5 mm long, terminating in a conical umbo of densely aggregate cells.

Gemmae

Not seen.

Figures

FIG. 4. — Riccardia martinii sp. nov.: A, thallus mats; B, dry thallus, showing white margins; C, moistened thallus; D, portion of thallus in dorsal view, showing thickened cell walls; E, apex of ultimate branch, showing papillae; F, main axis in cross section; G, ultimate branches in cross section; H, calyptra; I, portion of thallus with male branches. From Sass-Gyarmati 9613/CW, Vojko 9660/CS, Pócs 9602CU, 6877/K, Bardat JBMAD78 (PC0763890), Riccardia ramosissima (Steph) Grolle: J, thalli; K, main axis in cross section; L, ultimate branches in cross section; M, male branch; N, calyptra; O, upper portion of calyptra, showing umbo. From Reeb CR13Z51 (PC0763864), Pócs 6981/A, Jelinek s.n. (Type of Aneura compacta). Riccardia saccatiflora (Steph.) S.W.Arnell: P, thalli; Q, main axis in cross section; R, ultimate branches in cross section; S, portion of thallus with two female branch (left) and two male branches; T, calyptra. From Wigginton M1758b, Reeb CR11142 (PC0763883), Een M064, Rodriguez 182 (Type of Aneura saccatiflora). Riccardia vohimanensis Reeb & Gradst.: U, thalli; V, main axis in cross section; W, ultimate branch in cross section; X, sporophyte and calyptra with the vegetative expansion at its basis. From Reeb MTM1278 (PC0763879), CR13Z23 (PC0763868), O’Shea M7327b, Een M028. Scale bars: A-C, H-J, N, P, U, 1 mm; D-G, M, Q, T, V-X, 500 µm; K, L, R, 100 µm; O, S, 200 µm.