Pilotrichum cristatum Mitt.
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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
Pilotrichaceae
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Scientific Name
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Description
Species Description - Plants medium-sized to ± robust, in dull, green to yellow-green to golden-brown, often extensive patches. Stems creeping, with leaves greatly reduced, the primary branches erect or pendent, 2-10 cm long, usually ca. 4-6 cm long, regularly pinnate to bipinnate; in cross-section with 3-6 rows of small thick-walled colored cells surrounding larger thin- to firm-walled cells, central strand none; pseudoparaphyllia foliose; axillary hairs 2-celled, with a short brown basal cell and an elongate hyaline distal cell. Secondary branch leaves fairly crowded, erect to erect-spreading when dry, erect-spreading to spreading when moist, ovate, 0.8-1.2 mm long, mucronate, often retuse, concave, shortly auriculate-decurrent; margins subserrulate to subentire throughout, strongly incurved above, plane below or narrowly recurved; costa double, ± unequal, ± divergent throughout or parallel in upper 1/2-2/3, mostly subpercurrent, with a medium-high crest 1-3 cells high; cells mostly oval, sometimes rounded-oblong, smooth or low-prorulose, thick-walled, scarcely porose, apical cells sometimes somewhat longer in the base of the mucro, becoming longer, thicker-walled, and porose toward the insertion; alar cells not differentiated. Asexual propagula occasionally produced near costal apex, uniseriate, hyaline to light-brown, to ca. 8 cells long, roughened. Dioicous. Perichaetia conspicuous or not, often clustered, on primary branches and sometimes bases of secondary branches; leaves loosely erect, oblong, 1.1-1.7 mm long, mucronate to ± gradually short-acute; margins subentire throughout, narrowly incurved above, plane below; costa double, unequal, ± divergent throughout, ending ca.3/4 the leaf length, occasionally single or absent, not crested; cells oval in upper midleaf, rounded-oblong along margins, sometimes in apex, low-prorulose to smooth, thick-walled, ± porose, becoming longer, thicker-walled, and porose toward the insertion. Setae short, stout, somewhat roughened, reddish, 1.3-1.8 mm long, often curved; capsules exserted, erect, short-cylindric, symmetric, ca. 2 mm long; exothecial cells short-rectangular, firm-walled, not collenchymatous; annulus not seen; operculum short-rostrate from a high-conic base; exostome teeth pale, narrowly triangular, narrowly bordered, not shouldered, on the front surface with a straight or obscurely zig-zag median line, spiculose throughout, slightly trabeculate at back; endostome pale, spiculose, with a low basal membrane, segments slender, keeled, narrowly perforate, almost as long as or shorter than the teeth, cilia none. Spores spherical to oval, finely papillose, 15-20 µm diam. Calyptrae mitrate, lobed at base, hairy, the hairs ± straight, 2-4-seriate, smooth.
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Discussion
6. Pilotrichum cristatum Mitt., J. Linn. Soc., Bot. 12: 387. 1869; Callicosta cristata (Mitt.) Crosby, Bryologist 81: 437. 1978. Plate 29, figure 6; plate 32, figures 1-4 Pilotrichum mucronatum Mitt., J. Linn. Soc., Bot. 12: 389. 1869. Discussion. Pilotrichum cristatum is distinguished from all other Pilotrichum species by the usually retuse, sometimes just obtuse, and mucronate leaf apex. The leaf margins are incurved from the base of the mucro and often overlap one another. Also characteristic are the often short leaf cells. The plants often occupy slightly more mesic habitats than many of the other species in the genus.
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Distribution
Range. Cuba, Jamaica, Hispaniola (Haiti); growing on trees, logs, and limestone rocks, in mesic forests, at 300-1400 m.
Cuba South America| Jamaica South America| Haiti South America|