Riccardia inconspicua (Steph.) Reeb & Bardat

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 : 24

Riccardia inconspicua (Steph.) Reeb & Bardat

( Fig. 3 F-K)

Aneura inconspicua Steph. , Hedwigia 32: 23 (1893). — Type: Cameroon, Junger 5 (lecto-, here designated, G[G00067564]!; isolecto-, S-B20523!).

Riccardia tenuicostata Schiffn., Denkschriften der Kaiserlichen Akademie der Wissenschaften, Mathematisch-Naturwissenschaftliche Classe 67: 166 (1898). — Aneura tenuicostata (Schiffn.) Steph. , Species Hepaticarum 1: 245 (1899). — Type: Singapore ( Furuki 1994).

Aneura exigua Steph. , Species Hepaticarum 6: 25 (1917). — Type: Seychelles ( Reeb & Bardat 2014).

FURTHER SPECIMENS EXAMINED. — Cameroon. Ekundu N’dene, 16.III.1892, Dusén 841 (G00264075, PC0101721). Cameroon: Kumba, Banga, S. Bakundu Forest Reserve, 5°5’50”N, 9°18’35”E, 15.III.1948, Brenan & Jones 269 (E).

Madagascar. Alaotra-Mangoro, Maromizaha Reserve, 18°58’45”S, 48°27’51.8”E, 1011 m, 06.VII.2012, Reeb MTM1295* ( PC 0763882, TAN).

Seychelles. Mahé, Congo Rouge, 46°27’40.68’’S 55°26’12.768’’E, 820 m, 16.IV.2012 Senterre & Lariche SEY 6265* ( PC, SEY).

Tanzania. Morogoro, Uluguru Mts., Kilangala, SE of Bundunki, 1750-1950 m, 21.IX.1971, Pócs & Mwanjabe 6464 BP ( EGR).

DISTRIBUTION. — Paleotropical: tropical Africa ( Cameroon, Madagascar, Seychelles, Tanzania), tropical Asia, Australia (Queensland).

HABITAT. — On rotten wood in humid lowland and montane forests, between 120 and 1950 m.

DESCRIPTION

Dioicous.

Thallus

Green to pale-green when fresh, yellow to clear brown in herbarium, flaccid and fragile, glossy, mostly flat, very small, to 10 mm long, main axis creeping and attached to the substrate, branches erect, 1-2-pinnate, not palmate, branches alternate to subopposite, stolons rare, thallus margins with mucilage papillae.

Main axis

Irregularly to clearly defined, 150-300(-350) µm wide, in cross section plano-convex, (3-)4(-5) cells thick, margins acute, with a 1-2 cells wide wing.

Ultimate branches

Tongue-shaped to oblong, up to 1.5 mm long, in cross section 3-4 cells thick, lunate to concavo-convex, with 3-4 cells wide wings, the wings as wide as or wider than the midrib.

Mucilage papillae

On all branch margins (including sexual branches), especially on ultimate branches, simple to 2-3-furcate, to 100 µm long.

Oil bodies

Not seen.

Male branches

Solitary, straight to recurved, sessile or stalked, to 1.8 mm long, with up to 20 antheridial pairs, the margin with a scale-like wing equal to sometimes wider than the axis.

Female branches

Inserted laterally, straight, solitary or grouped, with up to 22 archegonial pairs, bordered by numerous, 4-5 cells long cilia, the cilia to 250 µm long, exceeding the width of the axis.

Calyptra

625-800 µm long, with an umbo of aggregate cells.

Gemmae

Abundant, present in all collections seen, 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.