Leskea

Hedwig

Sp. Musc. Frond., 211, plates 49 – 58, plate 59, figs. 1 – 5. 1801

Etymology: For Nathanael Gottfried Leske, 1751 – 1786, botanist of Lei p zig
Treatment appears in FNA Volume 28. Treatment on page 349. Mentioned on page 341, 342, 350, 379, 434, 475, 648.

Plants small, in mats, pale green, dark green, or brownish. Stems freely branched to subpinnate; paraphyllia few, linear-lanceolate, cells smooth; sparsely radiculose. Stem and branch leaves similar or differentiated. Stem leaves erect or somewhat recurved when dry, erect-spreading when moist, oblong-ovate or ovate-lanceolate, plicate on one side, 2-plicate, or plane; margins plane or ± recurved proximally, entire to subserrulate distally, limbidium absent; apex acute, acuminate, or obtuse, hair-point absent; costa single, subpercurrent or ending before apex, opaque, often flexuose-curved distally; alar cells weakly differentiated, subquadrate; medial and distal laminal cells irregularly quadrate-hexagonal, ± 1-papillose on abaxial or both surfaces, walls thick; apical cells ± quadrate except at very tip. Specialized asexual reproduction absent. Sexual condition autoicous; perichaetial leaves pale brown, erect, elongate, apex acuminate. Seta 0.4–1.2 cm. Capsule erect, cylindric to oblong-cylindric, symmetric to distinctly curved; annulus narrow or absent; operculum conic; peristome reduced; exostome teeth linear-lanceolate, usually cross striolate near base, sometimes densely papillose throughout; endostome basal membrane low, segments long-linear, cilia absent or rudimentary. Spores 9–18 µm, smooth to very finely papillose.

Distribution

North America, Central America, South America, Europe, Asia, Africa.

Discussion

Species 24 (4 in the flora).

Leskea occurs in terrestrial habitats in temperate, subtropical, and tropical regions. The leaves are somewhat asymmetric with proximal laminal cells somewhat longer than the more distal cells, which are obscure; the exostome teeth are incurved when dry; and the endostome is erect, pale, and papillose.

Selected References

None.

Key

1 Branch leaves 0.2-0.5 mm; distal laminal cells 4-7 µm. Leskea australis
1 Branch leaves 0.4-0.8 mm; distal laminal cells 6-11 µm > 2
2 Stem and branch leaves differentiated, stem leaves longer than broad; apices ± obliquely acuminate and subsecund; branches somewhat curved at apices; capsules subcylindric, curved. Leskea polycarpa
2 Stem and branch leaves similar, not much longer than broad; apices not oblique or subsecund; branches not curved at apices; capsules oblong-cylindric, straight or slightly curved > 3
3 Branches ± tightly foliate; leaf apices acute or sometimes narrowly blunt; leaves ± 2-plicate; margins irregularly revolute proximally, especially when dry; endostome segments as long as exostome teeth; operculum ± pointed. Leskea gracilescens
3 Branches loosely foliate; leaf apices rounded-obtuse to sometimes acute or acuminate; leaves not plicate (stem leaves occasionally slightly plicate); margins not revolute; endostome segments less than 1/3 exostome teeth length; operculum blunt. Leskea obscura