Thamnobryum

Plants medium-sized to large, dendroid, dark green to yellow-green, slightly shiny to dull. Stems forming stipe perpendicular to substrate, pinnate to sparsely branched distally; paraphyllia absent. Secondary stem leaves erect to erect-spreading, ovate, somewhat asymmetric, concave; margins entire proximally, serrate at apex, teeth straight; apex broadly acute to obtuse; costa single, stout, subpercurrent; basal and medial distal laminal cells linear to rectangular, walls pitted or not. Sexual condition synoicous, autoicous, or dioicous; perichaetial inner leaves oblong, tapering to subula. Seta 1 cm. Capsule cylindric; exostome teeth linear-lanceolate, striate basally, becoming striate with overlying papillae, papillose at apex; endostome basal membrane high, segments papillose. Spores 10 µm.

Distribution

North America, Mexico, West Indies, Central America, South America, Europe, Asia, Africa, Australia.

Discussion

Species 42 (2 in the flora).

Thamnobryum is distinguished from other dendroid mosses in the flora by the stout costa and the branches mostly hanging, not upright as in Climacium. The pseudoparaphyllia are foliose. The primary stem leaves are appressed to erect-spreading and deltoid, with entire margins, acute apices, single costa, and irregularly rhomboidal to rectangular distal medial laminal cells. The stem leaf costae have 1–5 teeth distally. The stem leaf apical cells are hexagonal, rhombic, or rhomboidal. The branch leaves are concave with broadly acute to acuminate apices and rectangular basal and distal medial laminal cells. The inner perichaetial leaves are erect to erect-spreading, 1.5–2 mm, with margins entire, apex acute, costa single, slender, to ± mid leaf, basal laminal cells rectangular with pitted walls, distal medial cells linear to rectangular, and apical cells rhomboidal. The seta is reddish brown. The capsule is horizontal with endostome cilia present.

Selected References

None.

Lower Taxa

Thamnobryum alleghaniense, Thamnobryum neckeroides

Key

1	Branch leaves ovate, 1.5-2 × 0.5-0.6 mm; apices acute to acuminate; margins coarsely serrate at apex; apical laminal cells elongate-rhombic, more than 2:1.	Thamnobryum alleghaniense
1	Branch leaves oblong-ovate to ovate, 1-2.2 × 0.5-0.8 mm; apices obtuse to broadly acute; margins serrate at apex; apical laminal cells subquadrate to short-rhomboidal, 2:1.	Thamnobryum neckeroides