Riccardia regnellii (Ǻngstr.) K.G.Hell

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

Riccardia regnellii (Ǻngstr.) K.G.Hell

Pseudoneura regnellii Ǻngstr., Öfversigt af Kongliche Vetenskaps- Akademien, Förhändlinger 33: 90 (1876). — Riccardia regnellii (Ǻngstr.) K.G.Hell, Boletim da Faculdade de Filosofia, Ciências e Letras, Universidade de São Paulo, Botânica 25: 110 (1969). — Type: Brazil. Minas Gerais, Caldas, Regnell s.n. (lecto-, designated by Gradstein & Reeb [2018a], S-B260631!; isolecto-, G[G00282990]!).

Aneura amazonica Spruce, Transactions & Proceedings of the Botanical Society of Edinburgh 15: 545 (1885). — Riccardia amazonica (Spruce) Gradst. & Hekking , Journal of the Hattori Botanical Laboratory 45: 129 (1979). — Type: Venezuela. San Carlos del Río Negro, “in trunco putrido”, Spruce H16 (lecto-, designated by Meenks & Pócs [1985], MANCH[MANCH-cc1680]!); syn. fide Gradstein & Reeb (2018a).

Aneura fendleri Steph. , Hedwigia 32: 20 (1893). — Riccardia fendleri (Steph.) Pagán , The Bryologist 45: 80 (1942). — Type: Trinidad. Fendler s.n. (lecto-, designated here, G[G00066647]! autoicous). Guadeloupe. Marie s.n. (syn-, n.v.), syn. nov.

Aneura subsimplex Steph. , Hedwigia 32: 27 (1893). — Riccardia subsimplex (Steph.) Pagán , The Bryologist 45: 81 (1942). — Type: Cuba. Wright s.n. (holo-, G[G000066692]!), syn. nov.

Aneura planifrons Spruce , Journal of the Linnean Society, Botany 30: 368 (1895). — Riccardia planifrons (Spruce) Pagán , The Bryologist 45: 80 (1942). — Type: St. Vincent. “in monte St. Andreae, ad Musarum vaginas marcescentes”, II.1892, W. R. Elliott 145 (not found), syn. nov.

SPECIMENS EXAMINED FROM THE FRENCH ANTILLES. Guadeloupe. Matouba, rivière Rouge, 650 m, 14.I.1961, Le Gallo 1760, small form from lateritic soil (PC); St. Marie, Capesterre, 22.II.1962, Le Gallo 1292, 1269, 1298, small forms from lateritic soil (PC); Moscou, Palmiste, 620 m, 01.III.1962, Le Gallo 1293 (PC); “sur les arbrisseaux”, Morne Graine Verte, Matelyane, A. Duss 71, det. Pagán as A. planifrons (NY[00790036]); Rivière Quiock, 16°10’48”N, 61°41’35”W, 200 m, 10.IV.2011, Lavocat Bernard 1436; Carbet Falls, 16°02’48”N, 61°38’53”W, 870 m, 24.IV.2012, Lavocat Bernard 1652; 16°02’41”N, 61°38’30”W, 640 m, 28.VII.2013, Lavocat Bernard 1895.

Martinique. Bois du Lorrain entre la Champ Flore et du Lorrain, 650 m, A. Duss 312 (NY[790038]), 442 (NY), 490 (NY); Mount Pelée, 14°48’36”N, 61°10’14”W, 1160 m, 9.VIII.2012, Lavocat Bernard 1747; 14°48’44”N, 61°09’48”W, 1205 m, 19.V.2014; 14°48’46”N, 61°09’47”W, 1245 m, 19.V.2014; Morne Tranchette, Morne Vert, 14°41’52”N, 61°07’25”W, 660 m, 8.VIII.2017, Lavocat Bernard 17802; Piton Lacroix, 14°41’52”N, 61°07’10”W, 800 m, 8.VIII.2017, Lavocat Bernard 17808, 17829.

DISTRIBUTION AND HABITAT. — Widespread in tropical America, occurring on soil, shaded rock and decaying wood in lowland and montane rainforests up to the páramo belt. The species has also been recorded from Africa but the African material belongs to R. longispica (Steph.) Pearson ( Gradstein & Reeb 2018a; Reeb & Gradstein 2020). In the West Indies reported from the Dominican Republic ( Schäfer-Verwimp & Pócs 2009), Guadeloupe ( Lavocat Bernard & Reeb 2016) and Martinique ( Lavocat Bernard 2018).

ILLUSTRATIONS. — Gradstein & Ilkiu-Borges (2009), Gradstein & Reeb (2018b).

REMARKS

Riccardia regnellii is a common and very variable, heteroicous (dioicous or monoicous) neotropical species that is recognized by prostrate, irregularly 1-2-pinnate thalli (0.3-0.6 mm wide and to 1.5 cm long) without stolons, a 3-7 cell thick, plano-convex axis without or with a narrow wing, and tongue-shaped or linear, flat, broadly winged branches. The epidermis cells are smaller than the inner cells, the branch wings are narrower than the costa and the surface cells of the branches are often arranged in oblique rows. Dioicous plants are sexually dimorphous with male thalli being slightly smaller and more elongate than female thalli; the two types of thalli may occur mixed in the same mat ( Gradstein & Reeb 2018a, b).

Riccardia fendleri and R. subsimplex are an autoicous, West Indian phenotype of R. regnellii with winged male branches (wing 1-3 cells wide). Possibly this phenotype derves recognition as a separarate variety; this need further study.

Pagán (1942) recorded R. subsimplex from Guadeloupe and Martinique but the material on which these records were based (A. Duss 182, NY[611574]; 182a, NY[611573]; 457, NY) belongs to R. stipatiflora .

Riccardia planifrons was originally described from St. Vincent; we have not been able to locate the type material of the species, it is lacking in MANCH (Spruce herbarium), BM and G. A putative type specimen received on loan from BM (BM013777343) with the collection number of the holotype, “ W. R. Elliott 145 ”, was from a different location, “on dead palm leaves at the foot of Souffrière Mt.”, and contained Cyclolejeunea convexistipa (Lehm. & Lindenb.) A.Evans and cyanobacteria, but no Riccardia . Based on the original description and the illustration of the type ( Stephani 1985), we believe that R. planifrons is a synonym of R. regnellii . Indeed, the material recorded from Guadeloupe (A. Duss 71, NY[790036]) by Pagán (1942) belongs to R. regnellii .

In Guadeloupe R. regnellii varies considerably in size and plants from lateritic soil are smaller and less elongate than those growing on bark and rotten wood (observed in plants collected by Le Gallo). The small terrestrial phenotype might be described as a different form, similar to R. longispica (Steph.) Pearson fo. erosa Reeb & Gradst. from Africa ( Reeb & Gradstein 2020). This needs further study based on material from throughout the range of R. regnellii . The molecular clustering reflects the geographic differentiation between Africa and the Neotropics, mainly due to GMYC analysis ( Fig. 1 ) resulting in a larger cluster grouping the two species ( Fig. 2 ).

The specimens from the French Antilles recorded as R. cataractarum by Lavocat Bernard & Reeb (2016) and Lavocat Bernard (2018) belong to R. regnellii .

Figures

FIG. 1. — Species delimitation results plotted in regards of the Bayesian tree obtained with Beast for the GMYC analysis. Posterior probabilities> 0.9 were kept. The number for species proposed by each method is given in the highest line. Final species hypothesis are plotted on the right. Specimens from West Indies are colored in red. Abbreviations: ECU, Ecuador; REU, La Réunion; FRA, France; MAD, Madagascar; GLP, Guadeloupe; SHN, Saint Helena; MTQ, Martinique; USA, United States; COM, Comoros; IDN, Indonesia; UGA, Uganda; BES, Saba.

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.