Rhacopilopsis trinitensis (Müll.Hal.) E.Britton & Dixon
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Authority
Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
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Family
Hypnaceae
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Scientific Name
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Description
Species Description - Plants slender to medium-sized, in ± lustrous, soft, mostly pale-green, thin mats. Stems long-creeping, to 10 cm long, often regularly pinnate, the branches complanate-foliate, <1 cm long; in cross-section with 2-4 rows of small thick-walled cells surrounding larger thinner-walled cells, central strand none; pseudoparaphyllia filamentous; axillary hairs with a single relatively long or 2 short brown basal cells and 2-3 elongate hyaline distal cells. Stem and branch leaves somewhat differentiated, ventral, dorsal and lateral stem leaves strongly differentiated, the ventral ones symmetric, oblong-ovate, 0.65-0.95 mm long, gradually long-acuminate, the dorsal ones somewhat asymmetric, ovate, 1-1.3 mm long, gradually acuminate, concave, the lateral ones strongly asymmetric, often cultriform, ovate-oblong, 0.85-1.2 mm long, ± abruptly acuminate, concave; all stem leaves with margins distantly subserrulate throughout, plane; costa short and double; 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 pm long, sometimes absent on one side of lateral leaves, with 512 rhomboidal to subquadrate cells directly above the enlarged ones. Branch leaves with dorsal and lateral leaves differentiated, the dorsal ones 1/2 as many as the lateral ones, symmetric, erect-spreading, lanceolate, 0.8-1.1 mm long, gradually acuminate, the lateral ones somewhat asymmetric, wide-spreading, sometimes subfalcate, oblong-ovate, 1.1-1.3 mm long, gradually or ± abruptly acuminate, somewhat concave; all branch leaves with 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. Sporophytes not seen.
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Discussion
1. Rhacopilopsis trinitensis (Müll. Hal.) E. Britton & Dixon in Dixon, J. Bot. 60: 88. 1922; Hypnum trinitense Müll. Hal., Syn. Muse. Frond. 2: 284. 1851; Ectropothecium trinitense (Müll. Hal.) Mitt., J. Linn. Soc., Bot. 12: 514. 1869. Plate 121, figures 1-10 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, the Guianas, and northern Andean South America. Although I have not critically evaluated Cardot’s (1909, cf. p. 50) two varieties, gracilis and acuminata, that were described from Africa but have also been reported from the New World (Dixon, 1922), they are surely unworthy of taxonomic recognition.
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Distribution
Range. Guatemala to Panama, northern South America, Brazil, Trinidad, central Africa, Madagascar; Guadeloupe, Dominica, Martinique; growing on tree trunks, especially at the bases, occasionally on logs, mostly in moist forests, at 400-900 m.
Central America| Venezuela South America| Colombia South America| Guyana South America| Suriname South America| French Guiana South America| Brazil South America| Ecuador South America| Trinidad and Tobago South America| Cameroon Africa| Central African Republic Africa| Democratic Republic of the Congo Africa| Republic of the Congo Africa| Equatorial Guinea Africa| Gabon Africa| São Tomé and Príncipe Africa| Madagascar Africa| Guadeloupe South America| Dominica South America| Martinique South America|