Pilotrichum affine (Hook.) Brid.

Authority

Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.

Family

Pilotrichaceae

Scientific Name

Pilotrichum affine (Hook.) Brid.

Description

Species Description - Plants medium-sized, in ± lustrous, yellow-green to golden, brown-tinged, often extensive patches. Stems creeping, with leaves smaller, more triangular and more broadly inserted than branch leaves, the primary branches erect, 2-8 cm tall, usually ca. 3 cm tall, closely pinnate, rarely bipinnate; in cross-section with 3-5 rows of small thick-walled small-lumened colored cells surrounding larger firm-walled cells, central strand none; pseudopa-raphyllia filamentous to narrowly foliose; axillary hairs 2-celled, with a short brown basal cell and an elongate hyaline distal cell. Secondary branch leaves fairly crowded, slightly contorted and erect when dry, wide-spreading when moist, narrowly ovate, often with an expanded base, 1.2-1.7 mm long, gradually acuminate, slightly concave, ± short-decurrent; margins subentire throughout, plane; costa double, unequal, ± parallel in upper 1/2-1/3, ending ca. 3/4 the leaf length to subpercurrent, with a medium-high crest to 4 cells high; cells shortly rounded-oblong to oval, low-prorulose, thick-walled, not particularly porose, apical cells sometimes somewhat longer, becoming longer and porose toward the insertion; alar cells not differentiated. Asexual propagula on basal 2/3 of costa or almost to apex, uniseriate, hyaline to light-brown, to ca. 15 cells long, roughened. Dioicous. Perichaetia ± inconspicuous, usually on primary branches, often in pairs; leaves erect with flexuose apices, narrowly triangular-lanceolate, 1.2-1.9 mm long, gradually acuminate, somewhat decurrent; margins serrulate above, subentire below, plane; costa double, unequal, ± parallel, ending near midleaf, not crested; cells oblong to linear, inconspicuously prorulose to smooth, thick-walled, porose, sometimes shorter in the apex, often colored at the insertion. Setae short, stout, smooth, reddish, 0.7-1.4 mm long, straight; capsules exserted, erect, short-cylindric, symmetric, ca. 1.5 mm long; exothecial cells rectangular, firm-walled, not collenchymatous; annulus of 2-3 rows of overlapping, rectangular cells; operculum short-rostrate from a high-conic base; peristome inserted below the mouth, exostome teeth pale, narrowly triangular, not bordered, not shouldered, on the front surface with a straight or obscurely zig-zag median line, papillose-spiculose throughout, slightly trabeculate at back; endostome pale, papillose-spiculose, with a low basal membrane, segments slender, keeled, not perforate, shorter than the teeth, cilia none. Spores spherical to oval, finely roughened, almost smooth, 12-25 µm diam. Calyptrae mitrate, lobed at base, densely hairy, the hairs ± straight, 1-2-seriate, smooth.

Discussion

4. Pilotrichum affine (Hook.) Brid., Bryol. Univ. 2: 261. 1827; Neckera affinis Hook., Musci Exot. 2: 122. 1819; Daltonia affinis (Hook.) Am., Mém. Soc. Hist. Nat. Paris 5: 302. 1826; Hookeria neglecta Hampe, Linnaea 20: 97. 1847, non H. affinis Arn., Trans. Wernerian Nat. Hist. Soc. 5(1); 202. 1824 [= Callicostella depressa (Hedw.) A. Jaeger]; Callicosta affinis (Hook.) Müll. Hal., Linnaea 21: 188. 1848; Eupilotrichum affine (Hook.) Müll. Hal., Hedwigia 37: 242. 1898, comb, inval. Plate 29, figure 4; plate 31, figures 1-5 Discussion. Although the type collection by Menzies is given as St. Vincent, Crosby (1969: 333) suggested that the locality data are in error. No modem collections are known from the Lesser Antilles. Pilotrichum affine is characterized by its narrowly ovate, acuminate leaves. It differs from P. debile, the only other acuminate-leaved species, in its smaller stature, scarcely contorted leaves, broader leaf bases, and shorter laminai cells. It is also much more densely pinnate.

Distribution

Range. Cuba, Jamaica, Hispaniola (Haiti and Dominican Republic), St. Vincent (?, see following note); growing on trees, lianas, logs, rocks, and humus, in moist forests, at 450-1800 m.

Cuba South America| Jamaica South America| Haiti South America| Dominican Republic South America| Saint Vincent and the Grenadines South America|