Vesicularia vesicularis (Schwägr.) Broth.
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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
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Species Description - Plants smallish to medium-sized, in somewhat lustrous, flaccid to soft, dark- to pale-green to golden, often extensive, thin, flattish mats. Stems creeping, often fragile, often regularly pinnate but sometimes irregularly but freely branched, the branches simple; in cross-section with 2-4 rows of small firm-walled cells surrounding larger firm-walled cells, central strand small, of thin-walled cells; pseudoparaphyllia filamentous, often biseriate below; axillary hairs with a single short brown basal cell and 3-5 elongate hyaline distal cells. Stem and branch leaves differentiated, crowded to lax, often contorted when dry, sometimes falcate-secund, stem leaves broadly inserted, triangular, 0.8-1.2 mm long, gradually acuminate; margins entire to serrulate, plane; costa short and double or absent; cells long-hexagonal, broad, 4-6:1, smooth, mostly thin-walled, becoming broader and rectangular toward the insertion; alar cells not differentiated. Branch leaves mostly contorted when dry, appearing narrower than when moist, the dorsal and lateral ones ovate to broadly oblong-lanceolate, 0.70-0.95 mm long, apiculate to gradually acuminate; margins entire to serrulate, plane; costa short and double or absent; cells lax, hexagonal to long-hexagonal, 1-12:1, smooth, thin- to firm-walled, becoming shorter and rectangular toward the insertion; alar cells not differentiated; ventral leaves sometimes differentiated, if so, then narrower, longer acuminate, and with narrower, longer cells. Asexual propagula not seen. Autoicous. Perichaetial leaves erect, often with spreading apices, oblong-lanceolate, 1.2-1.7 mm long, gradually acuminate; margins entire to serrulate, plane; costa none; cells long-hexagonal, 5-7:1, smooth, firm- to thick-walled, becoming shorter, broader, and rectangular below; alar cells not differentiated. Setae elongate, slender, smooth, reddish, 1.5-2 cm long, flexuose, curved just below the urn; capsules horizontal to pendent, short, ovoid to short-cylindric, symmetric or asymmetric, ca. 1 mm long, sometimes constricted below the mouth when dry (when capsule somewhat longer than usual); exothecial cells quadrate to rectangular, thin-walled, collenchymatous; annulus of 2(-3) rows of subquadrate firm-walled cells with 1(-2) rows of inflated cells above them, early deciduous; operculum apiculate to short conic-rostrate; exostome teeth shouldered, bordered, on the front surface cross-striolate below, coarsely papillose above, trabeculate at back; en-dostome with a high, smooth basal membrane, segments papillose, broad, keeled, narrowly perforate, ca. as long as the teeth, cilia papillose, mostly in pairs. Spores spherical, finely papillose, 1114 µm diam. Calyptrae cucullate, naked, smooth.
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Discussion
1. Vesicularia vesicularis (Schwagr.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1094. 1908; Hypnum vesiculare Schwagr., Sp. Musc. Frond. Suppl. 2(2, 2): 167. 1827 [Apr-May]; Ectropothecium vesiculare (Schwagr.) Mitt., J. Linn. Soc., Bot. 12: 518. 1869. Plates 122, 123 Discussion. Vesicularia vesicularis grows throughout the West Indies on a wide range of moist substrates from limestone and mud to rotting logs. It is extremely variable. Although I have recognized four varieties, I am not convinced of their biological significance. Rather, they may be no more than ecological modifications instead of genetic adaptations to different habitats. The four varieties form a linear progression of morphological variation that appears to correlate with degrees of humidity and exposure. In perpetually shaded and humid environments the var. vesicularis predominates; in somewhat sunnier habitats the var. rutilans is most common. Intermediates are frequently encountered. In exposed situations, or curiously, in periodically inundated ones, the var. portoricensis is most frequently found. The var. crassicaulis, known in the West Indies from only two collections, seems to have the most mesic requirements. The primary reason for taxonomic categorization is the extreme difference between the form of plants at different ends of the environmental spectrum. Honestly, though, I often do not bother with varietal pigeonholing when identifying material.