An evaluation of the endemic bryophyte flora of Guadeloupe Author Gradstein, S. Robbert Muséum National d’Histoire Naturelle - Sorbonne Universités, Institut de Systématique, Évolution, Biodiversité (UMR 7205), BP 39, 57 rue Cuvier, 75005 Paris (France) robbert. gradstein @ mnhn. fr (corresponding author) gradstein@mnhn.fr Author Bernard, Elisabeth Lavocat Moreau, 97128 Goyave, Guadeloupe, F. W. I. Corresponding member of the Muséum National d’Histoire Naturelle, Institut de Systématique, Évolution, Biodiversité, 75005 Paris (France) lisalavocat @ hotmail. com lisalavocat@hotmail.com text Cryptogamie, Bryologie 2020 2020-10-14 20 15 205 214 http://dx.doi.org/10.11646/zootaxa.4878.3.2 journal article 10.5252/cryptogamie-bryologie2020v41a15 1776-0992 7822144 Riccardia innovans (Steph.) Pagán ( Figs 2 -4) The Bryologist 45: 80 (1942) . — Basionym: Aneura innovans Steph. , in Urban, Symbolae Antillarum 2: 470 (1901) . — Type : Guadeloupe , Savane-à-Mulets, «Sur les arbrisseaux », 1901, Duss FIG. 1. — Isotypes of Frullania trigona L.Clark, Jovet-Ast & Frye (PC). 484, ex hb. Urban (lecto-, designated here, G[G00066662!], c . gyn.; isolecto-, NY n.v., fide Pagán 1942). Description The outstanding characters of R. innovans are the very delicate, 2-pinnate plants with a very narrow (150-250 µm in diameter), biconvex, almost wingless axis and numerous long and narrow, linear to subulate branches. The branches are only little narrower than the axis, plano-convex, obliquely to widely spreading, usually tapering to narrow tips, and narrowly winged by 1-2 cell wide wings. The presence of small scales on the calyptra, made up of large cells, may be a further characteristic of the species. The plants are dioicous; gemmae have not been observed. Remarks Riccardia innovans approaches R. regnellii (Ångstr.) K.G.Hell , but the latter is a larger plant with a flat axis (not biconvex) and with broader, frequently tongue-shaped branches. In the type material, some R. regnellii plants are growing mixed in the dense mat of R. innovans and are immediately recognized by their much larger size. Riccardia innovans is thus far only known from the type . A field search by the second author in the type locality and elsewhere has not revealed further populations of the species. The taxonomic relationships of the species will be dealt with in a comprehensive study on the genus Riccardia in Guadeloupe (Lavocat Bernard & Reeb in prep.).