Riccardia hymenophytoides (Spruce) Meenks

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 : 142

Riccardia hymenophytoides (Spruce) Meenks

Aneura hymenophytoides Spruce, Transactions & Proceedings of the Botanical Society of Edinburgh 15: 549 (1885). — Riccardia hymenophytoides (Spruce) Meenks , Nova Hedwigia 88: 101 (1987). — Type: Peru. Mt. Campana, 1200 m, Spruce s.n. (lecto-, designated by Gradstein & Reeb [2018b], G[G00282970]!).

Aneura sprucei Steph., Buletin de l’ Herbier Boissier 5: 844 (1897). — Riccardia sprucei (Steph.) Meenks & C.De Jong, Cryptogamie, Bryologie Lichénologie 6: 22 (1985). — Type: Venezuela. “Río Cauapuna, Fl. Negro”, Spruce s.n. (lecto-, designated byMeenks & de Jong [1985], MANCH[MANCH-cc1700]!); syn. fide Gradstein & Reeb (2018b).

SPECIMENS EXAMINED FROM THE FRENCH ANTILLES. — Guadeloupe. Carbet Falls, 16°02’41”N, 61°38’30”W, 640 m, 28.VII.2013, Lavocat Bernard & Reeb 1894; Forêt des Bains Jaunes, 16°01’49”N, 61°40’45”W, 750 m, 07.IX.2009, Lavocat Bernard 1162; Rivière La Rose, Goyave, 16°08’25”N, 61°36’33”W, 110 m, 06.II.2012, Lavocat Bernard 1583; Forêt de Frèdy, Goyave, 16°06’23”N, 61°35’56”W, 158 m, 03.VII.2017, Lavocat Bernard 17704.

Martinique. Morne Tranchette, Morne Vert, 14°41’55.5”N, 61°07’19.6”W, 760 m, 08.VIII.2017, Lavocat Bernard 17803, 17804.

DISTRIBUTION AND HABITAT. — A widespread neotropical species, occurring on shaded, often lateritic soil banks and on rotten wood at low to mid elevations. Recorded from the tropical Andes ( Venezuela to Bolivia), the Guianas, Brazil and the West Indies ( Gradstein & Reeb 2018b). In the West Indies reported from Puerto Rico and the Virgin Islands (Gradstein 1989), Cuba and Haïti ( Meenks 1987), the Dominican Republic ( Schäfer-Verwimp & Pócs 2009) and Guadeloupe ( Lavocat Bernard & Reeb 2016). New to Martinique.

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

REMARKS

Riccardia hymenophytoides is a heteroicous (autoicous or dioicous) species that is recognized by rather small, to 1-2 cm long thalli with a creeping, wingless, stolon-like, palmately branched axis without subepidermis and with ascending, flat, linear or tongue-shaped branches with broad transparent wings, the wings 4-8 cells wide, broader that the midrib, margins entire, wing cells rather small, 15-30(-35) µm wide. All thallus cells thin-walled and the epidermis cells of the axis are much smaller than medullary cells. Although the species was nested in R. fucoidea in the molecular analysis ( Rabeau et al. 2017; this paper), it is retained as a separate taxon. The GMYC method, which highlights supposed coalescence events, shows a difference in clustering among R. fucoidea and R. hymenophytoides ( Figs 1 ; 2 ). Riccardia hymenophytoides clearly differs from R. fucoidea on having a creeping axis without subepidermis and palmate branching. Moreover, the wing cells in R. hymenophytoides are much smaller than those in R. fucoidea . Riccardia sprucei is a rather delicate, monoicous phenotype of R. hymenophytoides from low elevation ( Gradstein & Reeb 2018b).

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.