Pireella angustifolia (Müll.Hal.) Arzeni
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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
Pterobryaceae
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Scientific Name
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Description
Species Description - Plants relatively robust, to ca. 8 cm tall, in green to golden, thin to dense, epiphytic colonies. Primary stems creeping, filiform, usually naked or with small, reduced leaves, turning ca. 90° and becoming the upright secondary stem (stipe), the creeping stem continuing by a bud from near the base of the stipe, stipes frondose and regularly pinnately branched, erect, often with flagellate branches, in cross-section with ca. 10 rows of small thick-walled reddish cells surrounding gradually larger firm-walled cells, central strand none; paraphyllia none; pseudoparaphyllia filamentous, numerous; axillary hairs with 2 short brown basal cells and 2-3 elongate hyaline distal cells. Stipe leaves squarrose-spreading from an expanded, broadly ovate, clasping base, 1.7-2.2(-3.2) mm long, abruptly acuminate; margins serrulate in the acumen, subentire below, plane; costa single, subpercurrent; cells linear, mostly smooth, very thick-walled, the lumina scarcely wider than the walls, somewhat porose, becoming shorter, broader, and more porose toward the yellowed insertion; alar cells few. Branch leaves spreading to wide-spreading, not in obvious spiral rows, little altered when dry, lanceolate, 1.4-2(-3.5) mm long, gradually broad-acuminate, concave, not plicate, sometimes deciduous and resulting in naked branches; margins usually serrulate above, subentire below, plane above, often narrowly recurved below; costa single, subpercurrent; cells at extreme apex oval, ca. 3:1, those at midleaf short-linear, ca. 6-10:1, smooth or prorulose, thick-walled, slightly porose, becoming broader and more porose toward the yellow or reddish insertion; alar cells scarcely differentiated. Asexual propagula often clustered in leaf axils on short stalks, uniseriate, 3-10-celled. Dioicous, rarely fertile. Perichaetia conspicuous; innermost leaves erect, oblong-lanceolate, 5-6 mm long, gradually long-acuminate; margins serrulate almost to base, more strongly so above, plane; costa single, long-excurrent, sometimes almost 1/2 the leaf length, smooth; cells linear, smooth, thick-walled, porose, becoming wider, thicker-walled, and more porose at the yellowed insertion. Setae very short, smooth, reddish, 0.3-0.5 mm long; capsules immersed, erect and symmetric, broadly cylindric, 2-2.5 mm long, thickened and shiny at mouth; exothecial cells irregularly hexagonal, ca. 1-2:1, thin- to firm-walled; annulus not differentiated; operculum not seen, reportedly conic-rostrate; exostome teeth yellow, not bordered or shouldered, often united in pairs at their apices, on the front surface the plates very thin, unornamented, often perforate, the inner layer of each tooth thickened in two vertical bands, smooth; endostome inconspicuous. Spores not seen, reportedly smooth, 22-36 µm diam. Calyptrae mitrate, pilose, smooth.
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Discussion
1. Pireella angustifolia (Müll. Hal.) Arzeni, Amer. Midl. Naturalist 52: 29. 1954; Pilotrichum angustifolium Miill. Hal., Syn. Musc. Frond. 2: 181. 1851; Pterobryon angustifolium (Müll. Hal.) Mitt., J. Linn. Soc., Bot. 12: 426. 1869. Plate 52, figures 1-8 Pterobryon angustifolium fo. flagellifera Besch., Ann. Sci. Nat. Bot. VI, 3: 223. 1876; Pterobryon angustifolium var. flagellifera (Besch.) Besch., J. Bot. (Morot) 8: 62. 1894; Pterobryon integrifolium Hampe ex Besch., J. Bot. (Morot) 8: 62. 1894 (fide Arzeni, 1954: 29, type not seen). Pterobryon angustifolium var. flabelliforme Besch. ex Arzeni, Amer. Midi. Naturalist 52: 29. 1954, nom. nud. in syn. Discussion. Pireella angustifolia is the largest and most commonly collected West Indian species in the genus, sometimes growing in large, lush colonies. It is distinguished macroscopically by its squarrose stipe leaves, spreading branch leaves, and its well-branched habit. Microscopically, the lanceolate branch leaves not rounded at the insertion and the linear branch leaf cells are diagnostic. Stunted forms may resemble P. pohlii but the squarrose-spreading stipe leaves should resolve any confusion. Pireella angustifolia seems most closely related to P filicina by the squarrose stipe leaves strongly differentiated from branch leaves, the similar perichaetial leaves, and the immersed capsules with a thickened mouth. Pireella filicina differs substantially, though, by the oval branch leaf cells, the erect branch leaves, and the smaller stature. Pireella husnotiana is probably also closely related to P angustifolia, but the appressed stipe leaves and the costa in all leaves ending near midleaf serve to clearly separate it.
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Distribution
Range. Mexico to Panama, Trinidad; Cuba, Jamaica, Hispaniola (Haiti and Dominican Republic), Virgin Islands (Tortola), Guadeloupe, Dominica, Martinique, St. Vincent, Barbados, Grenada; growing on tree trunks, logs, and limestone, in humid forests, at (300-)500-1200 m.
Mexico North America| Central America| Trinidad and Tobago South America| Cuba South America| Jamaica South America| Haiti South America| Dominican Republic South America| Virgin Islands South America| Guadeloupe South America| Dominica South America| Martinique South America| Saint Vincent and the Grenadines South America| Barbados South America| Grenada South America|