Pilotrichidium antillarum Besch.
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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 relatively robust, in dull, stiff, dark-green to golden to bronzish, often dense, extensive mats. Stems creeping, to ca. 7 cm long, mostly ca. 4 cm long, subpinnately or irregularly branched, obscurely complanate-foliate; in cross-section with a unistratose hyalodermis over 3-5 rows of small thick-walled cells surrounding larger thin-walled cells, central strand none; pseudoparaphyllia foliose, small; axillary hairs 2-celled, with a short brown basal cell and an elongate hyaline distal cell. Leaves ± contorted when dry, densely foliate, the lateral leaves erect-spreading, the dorsal and ventral ones erect, lateral and dorsal leaves oblong to oblong-ovate, 1-2 mm long, obtuse or truncate and mucronate to acute, ± asymmetric, occasionally undulate, shortly rounded to the insertion; margins entire throughout except for projecting papillae, denser above, plane or narrowly incurved in lower 1/2; costa double, strong, subpercurrent to short-excurrent, connivent at apex, projecting at apex as single spines; cells irregularly isodiametric, 1-3:1, 3-9 pan wide, smooth except those at margin with papillae projecting from margin, not over cell lumina, thin-walled and not porose (usually when leaf apex obtuse) to thick-walled and porose (usually when leaf apex acute), becoming rectangular, 2-6:1, firm- to thick-walled, and porose toward the insertion; alar cells not differentiated; ventral leaves sometimes differentiated, when so ovate to broadly ovate, acute, as long as to ca. 1/2 as long as other leaves, concave, otherwise similar. Asexual propagula unknown. Dioicous. Perichaetia small, inconspicuous, on stems and branches; leaves few, pale, ± erect, ovate with an oblong apex ca. as long or longer than the base, 1-1.3 (-1.5) mm long, acute; margins not bordered or with a single row of long-rectangular cells in base, entire, plane or narrowly incurved below; costa double, strong, subpercurrent or often short-excurrent, often marginal in acumen, projecting as spines at apex; cells oval, 1.5-4:1, smooth, thick-walled, not or obscurely porose, becoming sublinear and flexuose to long-rectangular, thick-walled and porose toward insertion. Setae elongate, obscurely roughened near apex, smooth below, reddish, 1.5-2.5(-3) cm long, curved at apex; capsules horizontal to pendent, short-cylindric, 1.2-1.7 mm long, with a short, ± roughened neck; exothecial cells short-rectangular, firm-walled, not collenchymatous; annulus of ca. 5 rows of small quadrate ± thin-walled cells; operculum conic-rostrate; exostome teeth narrowly triangular, orange, narrowly bordered, on the front surface with a broad pale median furrow with a zig-zag line down it, the plates cross-striolate below with fine overlying papillae, coarsely papillose above, somewhat trabeculate at back, smooth to finely papillose; endostome with a fairly high, finely but sparsely papillose basal membrane, segments papillose-spiculose, more strongly so above, keeled, perforate, with baffle-like crosswalls, ca. as long as the teeth, cilia none. Spores spherical, finely papillose, 914 µm diam. Calyptrae slenderly mitrate, falling before capsule maturity, shallowly and irregularly lobed at base, naked, lightly roughened at apex, smooth below.
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Discussion
Pilotrichidium brunnescens Besch., Ann. Sci. Nat. Bot. VI, 3: 244. 1876; Hookeria brunnescens Schimp. ex Besch., Ann. Sci. Nat. Bot. VI, 3; 244. 1876, nom. nud. in syn. Pilotrichidium antillarum var. complanatum Besch. ex Paris, Index Bryol. Suppl. 272. 1900, nom. nud. ? Pilotrichidium dussii Besch., J. Bot. (Morot) 16: 9. 1902 (type not seen). Pilotrichidium antillarum var. cubense Thér., Mem. Soc. Cub. Hist. Nat. “Felipe Poey” 14: 363. 1940. Discussion. Pilotrichidium antillarum is characterized by only slightly complanate-foliate plants with a stem hyalodermis, oblong leaves with strong costae, and smooth leaf cells. The leaf margins are entire except for projecting papillae. The setae are very long and stout with inclined capsules. The exostome teeth are furrowed, the exothecial cells are not collenchymatous, and the annulus is well developed. Pilotrichidium antillarum is less likely to be confused with P. callicostatum, which has pluripapillose leaf cells, than it is with Callicostella diatomophila. At times the two can be distressingly similar, but P antillarum can be distinguished by leaf margins entire except for projecting papillae rather than crenulate to serrulate, without papillae, as in C. diatomophila. If one is still insecure, a stem cross-section quickly separates the two: P. antillarum has a hyalodermis and C. diatomophila does not. There also appears to be a habitat difference in that C. diatomophila is typically on calcareous rocks, often submerged, whereas P. antillarum is (where tested) on noncalcareous rocks in moist, but not inundated sites.
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Distribution
Range. Honduras; Cuba, Puerto Rico, Guadeloupe, Dominica, Martinique, St. Vincent, Grenada; growing on rocks (usually—or always?— noncalcareous) and tree bases, in humid forests, often along streams, at 500-1000 m.
Honduras Central America| Cuba South America| Puerto Rico South America| Guadeloupe South America| Dominica South America| Martinique South America| Saint Vincent and the Grenadines South America| Grenada South America|