Monographs Details: Vesicularia
Authority: Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part Two: Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69 (2)
Family:Hypnaceae
Scientific Name:Vesicularia
Description:Genus Description - Plants of moderate size in flat, dark-, pale-green, or yellowish, ± shiny mats. Stems creeping, freely and often pinnately branched; branches horizontally spreading; pseudoparaphyllia filamentous. Ventral leaves usually differentiated, rather small and erect, usually lanceolate and acuminate. Dorsal and lateral leaves spreading to secund, generally somewhat larger and broader, somewhat asymmetric, oblong-lanceolate to broadly oblong-ovate, abmptly acute or apiculate to gradually acuminate; margins entire or sometimes ± sermlate above; costa very short and double or lacking; upper cells transparent, with ± conspicuous primordial utricles, hexagonal or oblong-hexagonal to short-rhomboidal, smooth, sometimes narrower in a single marginal row (forming an indistinct border); alar cells not much differentiated. Generally autoicous. Perichaetial leaves erect, subulate from an oblong-ovate base, sermlate at the margins. Setae slender and flexuose, curved at the tip, smooth; capsules small, horizontal to pendulous, ovoid to oblong-ovoid, contracted below a wide mouth when dry; exothecial cells thin-walled, ± thickened at the comers; annulus differentiated; operculum apiculate to short-rostrate from a convex or convex-conic base; exostome teeth cross-striolate below, bordered, trabeculate; endostome consisting of a high basal membrane, keeled and narrowly perforate segments, and well-developed cilia. Calyptrae naked.

Discussion:

Characteristics of this genus of moist or even wet habitats and considerable variability are short, broad capsules and a tendency for ventral leaves to be differentiated and leaf cells to be relatively short and lax. Buck's interpretation (1984b) of V. vesicularis as a complex of varieties, each poorly delimited, is followed here. His paper and also Salmon's study of 1904 help in elucidating the tropical American expressions of a notoriously bothersome genus. The short capsules have traditionally been considered indicative of a relationship to Ectropothecium and thus to the Hypnaceae. The epidermal cells of stems and branches commonly adhere to the bases ofleaves on dissection.

They are broader than the basal cells ofthe leaf, but in cross-section they prove to be small. Even though the epidermal cells are not larger than those within, one might ask whether there is some relationship to the Leucomiaceae, which also have broad, transparent leaf cells (see Allen, 1987).