Plants rather small, shiny. Stems irregularly 1(--2)-pinnate, the branches of unequal length; pseudoparaphyllia broadly rounded -foliose. Stem leaves oblong-ovate, broadly acuminate, decurrent; margins plane or somewhat recurved near the base, entire or ± serrulate; costa short and double to single and sometimes extending nearly to the midleaf; distal cells linear, thick-walled, smooth; alar cells small and subquadrate in rather sizable groups. Branch leaves smaller, more broadly acuminate, irregularly serrate distally. Sexual condition dioicous. Perichaetial leaves pale, sheathing at base, abruptly short-subulate, entire or nearly so. Setae red, smooth. Capsules suberect and ± curved to horizontal; annulus well differentiated; operculum conic; stomata in the short neck; peristome teeth pale yellow, cross-striolate below; endostome a high basal membrane with narrow, densely papillose segments perforated along the keel [with apparently single-nodose cilia, not seen]. Calyptrae and spores not seen.

Species 1 (1 in the flora): w North America.

This monotypic genus has been put in the Lembophyllaceae in the past but seems most closely related to the Hypnaceae as discussed by H. A. Crum (1987).

SELECTED REFERENCES

Crum, H. A. 1987. Bestia, Tripterocladium, and Isothecium: an explication of relationships. Bryologist 90: 40--42.

Lower Taxon

• Tripterocladium leucocladulum (J. K. A. Müller) Jaeger

Related Synonym(s):

• Hypnum leucocladulum J. K. A. Müller = Tripterocladium leucocladulum (J. K. A. Müller) Jaeger