26. Cheilolejeunea rigidula (Montagne) Schuster (1971: 105) .—

Lejeunea rigidula Nees ex Montagne (1840: 336) .

Type:— FRENCH GUIANA. Mont Serpent, Leprieur 257 (PC-Mont. No. 3655 lectotype designated by Grolle in sched. 1979?).— Fig. 17A–J.

Cheilolejeunea polyantha Evans (1902: 141), syn. fide Bastos & Gradstein (2020)

Cheilolejeunea serpentina (Mitten 1961: 112) Mizutani (1963: 171), syn. fide Bastos (2012a)

Plants yellowish green to light green, 0.9–2.0 mm wide. Stems 60–80 µm in diameter, 7(–10) epidermal cells in cross section, 12–30 × 8–21 µm; 10–11 medullary cells, 5–17 × 3–12 µm. Ventral merophytes 2 cells wide. Leaves imbricate, ovate-orbicular, flat, 260–380 × 340–430 µm, margin entire, apex rounded; trigones inconspicuous to conspicuous; basal cells 10–30 × 11–19 µm, median cells 12–24 × 8–18 µm, marginal cells 7–18 × 5–15 µm. Lobules ovoid, inflated, 1/4–1/3 of leaf length, free margin involute, apical tooth oblong and obtuse. Underleaves distant to subimbricate, orbicular, 135–270 × 170–320 µm, 2–3.5 × stem width, bifid to 1/4–1/3, with a V-shaped sinus, base cuneate to rounded. Dioicous. Androecia on short-specialized branches or intercalary on long shoots, 2–6 pairs of bracts globose. Gynoecia with lejeuneoid innovations, bracts spathulate, 490 × 330 µm, apex rounded; bracteole 380 × 320. Perianth with 4 strong keels, beak short. Vegetative reproduction unknown.

Distribution and habitat:—Pantropical, from southern United States to northern Argentina, including the Caribbean islands (Reiner-Drehwald 1998), and Africa (Bastos 2017). This species is widely distributed in the study area, growing on tree trunks, humus, and rocks in the coastal desert and semi-desert areas, inter-Andean deserts and semi-deserts, savanna, deciduous forests, lowland rainforest, lower and upper montane rainforests, from sea level to 2800 m, in the Puntarenas-Chiriquí, Guatuso-Talamanca, Guajira, Venezuelan, Sabana, Magdalena, Cauca, Chocó-Darién, Galápagos Islands (Gradstein 2021), and Western Ecuador provinces of the Pacific dominion (Fig. 18). Cheilolejeunea rigidula is the most common liverwort species in the Amazon basin (Campos et al. 2019). The records of C. rigidula that apparently are from the Páramo (Fig. 18), actually belong to the Cauca or Magdalena provinces.

Notes:—Characterized by having leaves orbicular, flat and apex rounded, underleaves 2–3.5 × the width of the stem, generally distant, dioicous sexuality, and with lejeuneoid innovations.

According to Bastos (2017) and Reiner-Drewald (1998) the lectotype was selected by R. Grolle “in sched.”, and there is an isosyntype, also designated by R. Grolle, in NY (NY-00920062).

Specimens examined:— BRAZIL. Amazonas: S „ o Gabriel da Cachoeira, 0°24’S, 66°23’W, 130 m, 5 July 1979, Yano 1713 (RB) . Rio de Janeiro: PARNA Tijuca, 22°56’51”S, 43°17’30”W, 607 m, 19 April 2006, Santos 443 (RB); Arboreto do Jardim Botânico do Rio de Janeiro, 15 December 2000, Costa 186 (RB); Santa Maria Madalena, Muribeca do Imbé, 21°53’73”S, 41°54’67”W, 582 m, 16 May 2017, Costa 1790 (RB) . COLOMBIA. Amazonas: Comunidad “Peña Roja”, 0°34’S, 72°08’W, 200 m, 8 July 2000, Idárraga 2338, 2349, 2353 (HUA); La Pedrera, 1°18’S, 69°36’N, 325 m, 9 March 1990, Churchill 16090-b (HUA) . Antioquia: Anori, El Retiro, 1500 m, 30 June 2016, Farfán C1423 (COL); Buriticá, vereda Higragra, 6°41’59.5”N, 75°53’30.6”O, 1067 m, Carmona 454 (HUA); Caracolí, 700 m, July 2017, Soto, s.n, (CUVC); Corcorna, 6°2’23.43”N, 75°7’1574”W, 830 m, 19 August 2016, Ordoñez 241 (HUA); Guatapé, vereda Santa Rita, 6°14’N, 75°10’W, 1850 m, 14 June 1997, Gutiérrez 1228 (HUA); Ituango, vereda Organí Medio, 7°15’3.540”N, 75°27’26.447”W, 197 m, 28 September 2015, Trujillo 7330 (HUA); Medellín, corregimiento Santa Elena, 6°16’27”N, 75°30’23”W, 2446 m, Londoño 133 (HUA); Urrao, vereda La Clara, 894 m, 19 July 2016, Morales 1065 (HUA). Boyacá: Paez, vereda Yamonta, 1345 m, 2017, Bravo 980, 981 (JBB); Santa María, vereda Caño Negro, 4°50’58”N, 73°16’53”W, 850 m, 7 October 2000, Aguirre 12898 (COL). Cauca: Morales, vereda Santa Barbara, 2°48’8.4”N, 76°43’10.5”W, August 2015, Gómez 556 (HUA). Chocó: Unguía, Cerro Tacarcuna, 1113 m, 4 April 2017, Gil-Novoa 3431 (UPTC); Nuquí, Amargal, 30 m, 6 August 1992, Gradstein, 8864 (COL). Córdoba: Montelíbano, May 2015, López 183 (HUA); Puerto Libertador, vereda Las Claras, 7°50’26.1”N, 75°41’53.5”O, 84 m, 5 April 2017, Pérez 519 (HUA). Guaviare: San José del Guaviare, 2°34’13.9’’ N, 72°53’05.9’’ W, 301 m, 4 December 2021, Gil-Novoa & Costa 3657, 3658 (UPTC). Huila: Acevedo, Macizo colombiano, 1°36’59” N, 76°6’15” W, 2100 m, 26 November 2011, Castillo 2358 I (COL). Magdalena: Santa Marta, cuchilla de San Lorenzo, 1800 m, 17 January 1967, Winkler C173 (COL). Meta: Villavicencio, Reserva Forestal Buena Vista, 4°9’09.1”N, 73°39’11.3”W, 645 m, April 2017, Medina 1422 (LLANOS). Nariño: Mosquera, 0 m, 9 November 1992, Linares 3b (COL). Quindío: Circacia, 4°35’N, 75°42’W, 1400 m, 15 April 2000, Orrego 337 (COL). Risaralda: west side of cordillera Occidental, 800 m, 29 July 1992, Gradstein 8639 (COL). Santander: Floridablanca, 7°70’14.8”N, 73°04’7.6”W, 1620–1871 m, 23 June 2014, Uribe 4315, 4322 (COL); Puerto Parra, 126 m, 2014, Castaño T3A2C1M2 (UPTC) . Tolima: Santa Isabel, 2960 m, 28 July 1980, Aguirre 1583 (COL); Venadillo, vereda Planadas, 1150 m, 11 August 1980, van Reen 2482 (COL) . COSTA RICA. San José: Pacific slope, 2000 feet, 4 October 1947, Svilha 47-736 (NY) . ECUADOR. Esmeraldas: Nr. Lita, 500 m, 20 August 2014, Wilson 04-20 (QCA) . PANAMÁ. Darien: Pinogana, 50 m, Salazar-A. 9200 (PMA) . Panamá: Barro Colorado, N . Salazar-A. 6079 (PMA); Panamá City, 22 April 1991, Gradstein 7886 (HUA, RB) . SURINAM. Nickerie: Bekker 1295ab (PMA) . VENEZUELA. Amazonas: near mouth of Cañon Grande, 140 m, 00°50’N, 66°10’W, January-February 1985, Halling s.n. (NY) . Merida: Distr. Campo Elias, 28 January 1976, Schuster 76-798 (F) .