Riccardia gasparii Reeb & Gradst., 2020

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 : 22-24

Riccardia gasparii Reeb & Gradst. sp. nov.

( Fig. 3 A-E)

DIAGNOSIS. — Dioicous. Thallus very fleshy, unwinged. Axis circular to biconvex, branches with rounded margins. Male branches stalked.

TYPE. — Madagascar. Alaotra-Mangoro, Vohimana Reserve, Grande Cascade, 18°55’43.6”S 49°29’56.6”E, 849 m, 30. VI.2012, Reeb MTV1246* (holo-, PC [ PC 0771050]; iso-, PC [ PC 0763876], TAN).

ETYMOLOGY. — Dedicated to Gaspard Reeb-Leurent, born 21/07/2015.

FURTHER SPECIMENS EXAMINED. — Madagascar. Alaotra-Mangoro, Vohimana Reserve, Grande Cascade, 18°55’43.6”S, 49°29’56.6”E, 849 m, 30.VI.2012, Reeb MTV1257 (PC, TAN); Maromizaha Reserve, 18°58’53.02”S, 48°27’50.1”E, 1002 m, 08.VII.2012, Reeb MTM12124 * (PC, TAN), 18°58’53.10”S, 48°27’51”E, 921 m, 08.VII.2012, Reeb MTM12127A *, MTM12133 *(PC0763885), MTM12134 * (PC0763884, TAN); Analanjirofo, Mananara Nord, E slope of Mahavoho hills, 16°27’S, 49°46.9’47.5”E, 220-300 m, 14.VIII.1998, Pócs & Szabo 9878/W (EGR).

DISTRIBUTION. — Alaotra-Mangoro and Analanjirofo regions of Madagascar.

HABITAT. — On rocks or boulders sometimes covered with a humus layer, in humid evergreen lowland and montane forests, between about 200 and 1000 m.

DESCRIPTION

Dioicous.

Thallus

Dull olive green to green when fresh, green to yellow brown in herbarium, very fleshy, rigid but not leathery (easily breaking when manipulated), to 2 cm long, 1-3-pinnate, not palmate, branches alternate to subopposite, reiterations sometimes present, stolons common, branches mostly wider than the main axis.

Main axis

Irregularly defined to well-defined in mature thalli, width variable, in cross section circular to ellipsoid at the base, circular to biconvex in the middle, 7-9(-16) cells thick, margins obtuse to rounded, not winged, epidermis cells 3-4× smaller than inner cells.

Primary branches

To 7 mm long, often overlapping.

Ultimate branches

Tongue-shaped to oblong, often sinuose (horizontally curved), to 6 mm long and 1.8 mm wide, in cross section plano-convex, 5-6(-7) cells thick, margins obtuse, not winged, epidermis cells 2-3× smaller than inner cells, branch apex rounded.

Mucilage papillae

Apical, not persistent.

Oil bodies

Not seen.

Male branches

On the main axis, solitary, stalked, with a scale-like wing narrower than the axis, the wing crenulate by larger cells.

Female branches

Laterally inserted, straight, bordered by a ciliate, scale-like wing.

Gemmae

Occasionally present, 2-celled.

Figures

FIG. 3. — Riccardia gasparii Reeb & Gradst. sp. nov.: A, thalli; B, main axis in cross section; C, ultimate branches in cross section; D, male branch; E, female branches.From Reeb MTV1246 (PC0771050), MTM12134 (PC0763884). Riccardia inconspicua (Steph) Reeb & Bardat:F, thalli;G, portion of ultimate branch with papillae; H, branched papilla (arrow); I, ultimate branch and male branch with papillae; J, main axis in cross section; K, ultimate branch in cross section. From Reeb MTM1295 (PC0763882), Pócs & Mwanjabe 6464/BP, Gardiner s.n. (Type of Aneura exigua), Jungner s.n. (Type of Aneura inconspicua). Riccardia longispica (Steph.) Pearson: L, thalli; M, main axis in cross section; N, ultimate branches in cross section; O, two male branches; P, female branch; Q, male branch. From Konya 9644/D, Bardat PF.2 (PC0763860), Pócs 9612/CD, De Lisle 199 (Type), Jones 1542b. Riccardia longispica (Steph.) Pearson phenotype erosa: R, thalli; S,two calyptra’s; T, main axis in cross section; U, thallus mat showing erect, concave ultimate branches; V, ultimate branch in cross section; W, branch apex with papillae and immature gemmae. From Porley U35b, Pócs 6052/CV, Reeb CRAE193 (PC0763859). Scale bars: A, F, L, R, U, 1 mm; B, C, M-P, Q, S, 500 µm; D, E, G-K, T, 200 µm; H, V, W, 100 µm.