Riccardia schwaneckei (Steph.) Pagán

Reeb, Catherine, Bernard, Elisabeth Lavocat & Gradstein, S. Robbert, 2022, An integrative taxonomic revision of Aneuraceae H. Klinggr. (Marchantiophyta) from Guadeloupe and Martinique, French West Indies, Cryptogamie, Bryologie 20 (8), pp. 135-152 : 144-146

Riccardia schwaneckei (Steph.) Pagán

( Fig. 4 G-M)

Aneura schwaneckei Steph. , Hedwigia 27: 278 (1888). — Riccardia schwaneckei (Steph.) Pagán , The Bryologist 42: 7 (1939). — Type: Puerto Rico. Schwanecke 55 (holo-, G[G00066688]! c.gyn., dioicous).

SPECIMENS EXAMINED FROM THE FRENCH ANTILLES. — Guadeloupe. Karukéra trail, 16°02’30”N, 61°38’38”W, 700 m, 28.II.2012, Lavocat Bernard 1599; La Soufrière, 16°02’40”N, 61°40’02”W, 1250 m, 24.VII.2013; Lavocat Bernard & Reeb 1863, 1864, 1874,

1875, CR13G9; Carbet Falls, 16°02’38”N, 61°38’29”W, 637 m, 28.VII.2013, Lavocat Bernard & Reeb 1893, 1899.

Martinique. Piton Lacroix, 14°41’54”N, 61°07’0”W, 980 m, 8.VIII.2018, Lavocat Bernard 17816.

DISTRIBUTION. — A species with a marked North-South disjunction in the Neotropics, occurring scattered in the West Indies ( Cuba, Puerto Rico and the Virgin Islands, Guadeloupe, Dominica, Martinique [new], St. Vincent; e.g. Meenks [unpubl.]; Schäfer-Verwimp [2010]; Lavocat Bernard & Reeb [2016]) and again in southern Brazil ( Stephani 1900; Gradstein & Costa 2003) and Uruguay ( Hässel de Menendez 1964). The record from the inner, equatorial tropics (Mt. Roraima, Guyana; Gradstein & Florschütz-de Waard 1989) is probably erroneous and based on misidentified material (SRGr, pers. obs.).

REMARKS

Riccardia schwaneckei is a dioicous species that is recognized by the rather broad, c. 1 mm wide, glossy green and fleshy, irregularly pinnate thalli with a notched apex, short and plump branches and a conspicuous, 1-3(-5) cells wide, hyaline wing (border) of enlarged cells with rather few chloroplast and oil bodies, the latter present in submarginal wing cells but being absent in the margin cells. Moreover, the margin cells of the wings are larger than the submarginal ones. The axis is plano-convex, c. 5-7 cells thick, and the epidermis cells are smaller than the medullary cells. By the rather fleshy, irregularly pinnate thallus with plump branches and a conspicuous hyaline wing of enlarged cells all around, R. schwaneckei resembles R. canaliculata (Nees) Kuntze (subg. Hyaloneura R.M.Schust.) from Southeast Asia. However, R. canaliculata differs in having strongly enlarged ventral epidermis cells with thick walls ( Furuki 1995). The putative relationship of R. schwaneckei to the subg. Hyaloneura needs further study. The two amplified specimens belong clearly to a separate cluster ( Fig. 2 ) but we need further analysis at a larger geographic scale to confirm our hypothesis.

Figures

FIG. 4. — Riccardia stipatiflora (Steph.) Pagán:A, thallus mat;B, isolated thallus from A.Duss 56 and ELB17603; C, female branches from A. Duss 56; D, male branch from ELB17603; E, main axis cross section from A. Duss 56; F, ultimate branch cross section from A. Duss 56. Riccardia schwaneckei (Steph.) Pagán: G, K, thallus mats on the field; H, ultimate branch apex; I, main axis cross section; J, ultimate branch cross section; L, M, branching patterns from ELB1599. Scale bars: A-D, K-M, 1 mm; E, F, H-J, 500 µm.

FIG. 2. — Conspecificity matrix built with COMA.Specimens from West Indies are colored in red and blue; species recorded in West Indies are colored in yellow; specimens outside of West Indies are colored in black; species not recorded in West Indies are colored in white.