Rhacopilopsis trinitensis Britton & Dixon 1927

Rhacopilopsis trinitensis

Rhacopilopsis trinitensis (Müll. Hal.) E. Britton & Dixon in Dixon, J. Bot. 60: 88. 1922. Hypnum trinitense Müll. Hal., Syn. Musc. Frond. 2: 284. 1851; Ectropothecium trinitense (Müll. Hal.) Mitt., J. Linn. Soc., Bot. 12: 514. 1869. Type: Trinidad. Ad Maraccas, Arima et montem Touche, Aug et Dec 1844 et 1847, Crüger (syntype: BM!).

Dimorphella brasiliensis Broth. & Herzog in Herzog, Arch. Bot. Est. São Paulo 1: 86. 1925. Type: Brazil. Minas Gerais: Serra da Caraça, 22 Jan 1921, Hoehne 8283 (173) (isotype: BM!).

See Watling and O’Shea (2000) for additional synonymy based on African types.

Plants slender to medium-sized, in ± thin mats, lustrous, soft, mostly pale green. Stems to 10 cm long, long-creeping, often regularly pinnate, the branches complanate-foliate, less than 1 cm long; stems in cross section with 2–4 rows of small thick-walled cells surrounding larger thinner walled cells, central strand none; pseudoparaphyllia filamentous; axillary hairs consisting of 1 relatively long or 2 short, brown basal cell(s) and 2–3 elongate, hyaline distal cells. Stem and branch leaves somewhat differentiated, ventral, dorsal and lateral stem leaves strongly differentiated, the ventral ones 0.65–0.95 mm long, symmetric, oblong-ovate, gradually long-acuminate, the dorsal ones 1.0–1.3 mm long, somewhat asymmetric, ovate, gradually acuminate, concave, the lateral ones 0.85–1.2 mm long, strongly asymmetric, often cultriform, ovate-oblong, ± abruptly acuminate, concave; all stem leaves with margins distantly subserrulate throughout, plane; costa short and double; median cells long-hexagonal to linear, 8–20:1, smooth but with thickened cell end walls, giving the impression of prorulae, firm-walled, becoming thicker-walled and somewhat porose toward the insertion; alar cells mostly yellow, 2–4 cells enlarged in extreme basal angles, oblong, to 55 µm long, sometimes absent on one side of lateral leaves, with 5–12 rhomboidal to subquadrate cells directly above the enlarged ones. Branch leaves with dorsal and lateral leaves differentiated, the dorsal ones 0.8–1.1 mm long, half as many as the lateral ones, symmetric, erect-spreading, lanceolate, gradually acuminate, the lateral ones 1.1–1.3 mm long, somewhat asymmetric, wide-spreading, sometimes subfalcate, oblong-ovate, gradually or ± abruptly acuminate, somewhat concave; branch leaf margins subentire to serrulate throughout, the lateral leaves more strongly toothed, plane or narrowly recurved above; costa short and double, rarely lacking; cells linear to linear-flexuose, 10–20:1, smooth, firm-walled, sometimes becoming shorter in the acumen, becoming thicker walled and somewhat porose toward the insertion; alar cells yellow, 3–5 cells enlarged in extreme basal angles, oblong, to 55 µm long, rarely absent on one side of lateral leaves, with 4–12 rhomboidal to subquadrate cells directly above the enlarged ones. Asexual propagula not seen. Dioicous. Perichaetial leaves long-attenuate; margins strongly toothed. Setae 17–30 mm long; capsules 1.8–2.5 mm long.

Distribution and ecology: Guatemala to Panama, northern South America, Brazil, Trinidad; elsewhere in central Africa and Madagascar; growing on tree trunks, especially at the bases, occasionally on logs, mostly in moist forests, at 400–900 m.

Illustrations in publications: Fig. 779 in Crum (1994b: 1051); Fig. 175 in Florschütz-de Waard and Veling (1996: 457); Pl. 121 in Buck (1998: 309); Fig. 143 in Buck (2003: 161); Fig. 183A–D in Bartram (1949: 415).

Discussion: The heterophyllous leaves with yellowed insertions are distinctive. The species is decidedly rare in the West Indies, although it is not uncommon in Trinidad, Central America, the Guianas, and northern Andean South America.

Although we have not critically evaluated Cardot’s (1909: 50) two varieties—Dimorphella pechuelii (“i”) (Müll. Hal.) Renauld & Cardot var. acuminata Cardot and D. pechuelii (“i”) (Müll. Hal.) Renauld & Cardot var. gracilis Cardot—that were described from Africa but which have also been reported from the New World (Dixon, 1922), we are unconvinced for this treatment that they deserve taxonomic recognition.

Selected specimens examined: GUATEMALA. Izabal: Valley of tributary of Río San Francisco del Mar, 3.2 km NE of Hopi, 19.3 km E of Entre Ríos, 10-20 m, Steyermark 39779 (F). HONDURAS. Yoro: Cordillera Nombre de Dios, N slope, ridge between Río Guán Guán and Quebrada Aguacatal, Allen 13599 (MO, NY). COSTA RICA. Alajuela: Río Jesús (Santiago) de San Ramón, Brenes 20420 (NY). Limón: Up to 4 km inland from Green Turtle Station and village of Tortuguero, Steere CR-5 (NY). San José: Vicinity of El General, Skutch 2694 (MO, NY). Puntarenas: Cocos Island, without locality, Holdridge 5194 (NY). PANAMA. Canal Area: Pipeline road leading NW from Gamboa, Crosby 10800 (MO). Chiriquí: Cerro Colorado, Chami Camp vicinity Cerro Colorado Mine, Allen 5000 (MO, NY). Colón: Along Santa Rita Ridge, ˜12.4 km NE from Boyd–Roosevelt Hwy., Crosby 4468 (MO). Darién: Pirre Massif just W of Cana, Allen 8889 (MO). Panamá: 6.5 km by road N of Lago Cerro Azul, Nee 9325 (MO, NY). Veraguas: 0.3 km beyond fork in road at Escuela Agricola Alto Piedra, Croat & Folsom 33939 (MO). Isla Bahia Honda: Without locality, Taylor 1110 (NY). DOMINICA. Syndicate Estate, ˜8 km S of Portsmouth, 605 m, Townsend 91/296 (NY). GUADELOUPE. Vicinity of Grand Etang, 400 m, Crosby & Crosby 4800 (MO, NY). MARTINIQUE. Without locality, 1899, Duss 86 (NY). TRINIDAD AND TOBAGO. Trinidad: Morne Bleu, Britton 2301 (NY). COLOMBIA. Arauca: Mpio. de Tame, S de Tame, entre San Lope, 485 m, Churchill et al. 18941 (NY). Boyacá: Mpio. de Cubara, ˜5 km E de Cubara, 300 m, Churchill et al. 18933 (NY); Casanare, Tauramena, 600 m, Uribe 4292(US). Caquetá: Transecto Neiva–San Vicentge del Caguán, 1200–1300 m, Churchill & Betancur 16897 (NY). Meta: Cordillera La Macarena, Schultes 11157 (NY, US); 20 km SE of Villavicencio, 480 m, Alston 7581 (US). Putumayo: ˜40 km NW of Puerto Asís, ˜305 m, King & Guevara C-1136 (US). Santander: E of Hacienda El Playón, NW of Bucaramanga, 1220–1373 m, Steere 7638 (NY). VENEZUELA. Amazonas: Along Río Mawarinuma, just outside Cañon Grande of Cerro de la Neblina, 140 m, Buck 12933 (NY). Apure: Reserva Forestal San Camilo, 250–280 m, Steyermark et al. 101723 (NY,US), 101730, 101850 (US); Quebrada La Azulita, 280 m, Steyermark et al. 101607 (US); 4.5–5 km N of San Camilo, 280 m, Steyermark et al. 101789 (US). Barinas: Distr. Pedraza, trail from Mesa de Canagua to Cerro de Filón, 600–880 m, Dorr et al. 7842 (NY). Bolivar: Gran Sabana, San Ignacio de Yuruaní, 850 m, Liesner 24230 (MO, NY). Sucre: Peninsula de Paria, entre Manacal y Los Pocitos de Santa Isabel, 700–900 m, Dumont et al. VE-7496 (NY); Cerro de Río Arriba, vecindad de “Los Positos,” 700 m, Steyermark & Rabe 96298 (US). Tachira: Oeste de Ayari, 200 m, Steyermark & Rabe 96644 (US). Yaracuy: Quebrada Honda, 17.3 km del pueblo de Aroa, 1100 m, Steyermark 105405 (NY, US). Zulia: Sierra de Perija, valley of the Río Socuy, 2400–2800 m, Griffin III 161 (NY). Hato La Vergareña, ˜75 km S of Cd. Piar, Pursell 8050 (US). GUYANA. Upper Mazaruni Dist.: Right bank of Mazaruni River, 05°52'N, 60°34'W, 473–641 m, Robinson 85-0081 (US). Kamakusa, along the upper Mazaruni River, Leng 4 (NY); NW portion of Kanuku Mountains, Mt. Iramaikpang, 850 m, Smith 3618 (NY, US); Essequibo River, Moraballi Creek, near Bartica, near sea level, Richards 241 (NY). Potaro-Siparuni Region: Kaieteur Natl. Park, 400 m, Pipoly 9904 (NY). SURINAM. Sipaliwini: Tafelberg, Maguire 24339 M3 (NY), Allen 20549 (MO, NY). FRENCH GUIANA. Approuague-Kaw: Pic Matécho, 590 m, Buck 37969 (NY), l’Inini Region: Mont Atachi Bacca, 03°33N, 53°55'W, 670 m, Cremers et al. 10444 (US). Maripasoula: Commune de Saül, vicinity of Eaux Claires, 200 m, Buck 18354 (NY). Roura: Kaw Mountains, Trésor Réserve Naturelle, 300 m, Buck 37769 (NY). ECUADOR. Napo: 6 km along Río Pano, 0°58'S, 77°52'W, 600 m, Holm-Nielsen & Jeppesen 702a (US). Pastaza: Lorocachi, 2 km del Río Curaray, 200 m, Jaramillo et al. 30715 (NY). Pichincha: ˜18 km NW of San Miguel de los Bancos, forest reserve of ENDESA, 800 m, Buck 10365 (NY). PERU. Madre de Dios: Los Amigos Biological Station, 250–320 m, Majestyk 4169 (NY). Near Pucallpa, Aug 1962, Worthley s.n. (US). BOLIVIA. La Paz: Franz Tamayo, Parque Nacional Madidi, 700–900 m, Fuentes et al. 4441 (MO, NY). BRAZIL. Amapá: Mpio. de Oiapoque, BR156 between Calçoene and Oiapoque, Mori & Cardoso 17108 (NY). Mato Grosso: Chapada dos Guimarães, Wasserfall Veu da Noiva, 500 m, Schäfer-Verwimp & Verwimp 8628 (NY). Pará: Serra do Cachimbo, Rio Jamanxím and vicinity, 300 m, Reese 16677 (NY, US); Serra Maze and vicinity, ˜05°55'S, 55°40'W, ˜100–200 m, Reese 16826 (US). Roraima: Pacaraima, 226 km N of Boa Vista, 1000 m, Buck et al. 1944 (NY).