Synopsis of the species of Cheilolejeunea (Marchantiophyta, Lejeuneaceae) in the Pacific dominion and Páramo province of tropical America Author Gil-Novoa, Jorge Enrique Programa de Pós-graduação em Botânica, Escola Nacional de Botânica Tropical, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro. Rua Pacheco Leão, Horto, 2040, 22460 - 080, Rio de Janeiro-RJ, Brazil. & Grupo Sistemática Biológica, Herbario UPTC, Universidad Pedagógica y Tecnológica de Colombia, Tunja, Boyacá, Colombia. Author Costa, Denise Pinheiro 0000-0001-9495-3029 Instituto de Pesquisas Jardim Botânico do Rio de Janeiro - IPJBRJ, Rua Pacheco Leão 915, 22460 - 030, Rio de Janeiro, RJ, Brazil. denisepinheirodacosta @ gmail. com; https: // orcid. org / 0000 - 0001 - 9495 - 3029 denisepinheirodacosta@gmail.com text Phytotaxa 2023 2023-03-14 587 2 73 120 http://dx.doi.org/10.11646/phytotaxa.587.2.1 journal article 10.11646/phytotaxa.587.2.1 1179-3163 7731813 10. Cheilolejeunea erostrata Schuster (1978: 427) . Type:— VENEZUELA . Tachira : Páramo de Tama , base of Pico de Banderas , 3140 m , 1 March 1976 , R . M . Schuster & L. Ruíz-Terán 76-1921e ( holotype F !) . Plants yellowish green to light brown, 1–1.6 mm wide. Ventral merophytes 2 cells wide. Leaves imbricate, orbicular to ovate-elongate, recurved at the apex, 680–950 × 400–650 µm; margin entire; apex acute to more commonly apiculate; dorsal and ventral margin slightly recurved; cells orbicular to ovate, mammillose to papillose on the dorsal side, conspicuous trigones; basal cells 20–30 × 15–23 µm, median cells 16–28 × 14–22 µm, marginal cells 10–17 × 8–16 µm. Lobules rectangular, 1/3–1/2 of leaf length, free margin slightly involute, tooth very short (1 cell long), observed in few lobules; keel slightly arched. Underleaves subimbricate to commonly imbricate, widely orbicular to obovate, 450– 500 × 470–530 µm, 5 x stem width, bifid to 1/5–1/3, with a V-shaped sinus, margin entire, insertion strongly curved. Autoicous. Androecia commonly on the main stem, 3–4 pairs of orbicular bracts. Gynoecia, with pycnolejeuneoid innovations, bracts obovate, apex acute. Perianth 5-keeled, keels weak to very strong, without beak. Distribution and habitat :—Endemic to the Venezuelan Andean páramos, on the border with Colombia ; this species is only known by the type collection, growing on the branches of Scrophulariaceae shrubs, in grass páramo between 3100–3500 m , in the Páramo province ( Fig. 8 ). Notes :—The species is characterized by the large plants with large, apparently flat and rectangular lobules (1/3– 1/2 of leaf length) but with a slightly involute free margin and very short lobule teeth (1 cell long), and perianths without a beak. More exploration is needed of the páramos between Colombia and Venezuela , to confirm the continued occurrence of the species in the area. Taking into account its extent of occurrence and number of locations ( Hallingbäck 1998 , UCN 2001), it is considered here as Critically Endangered (CR-B1a).