Hooker & Wilson

J. Bot. (Hooker) 4: 421, plate 25, fig. A. 1842.

Etymology: Greek klasma, fragment, and odon, tooth, alluding to irregularly bifid endostome
Treatment appears in FNA Volume 28. Treatment on page 433. Mentioned on page 405, 476, 654.

Plants small, in loose mats, dull to bright green. Stems creeping, densely terete-foliate, occasionally subsecund, irregularly branched, branches densely foliate; central strand absent; pseudoparaphyllia narrowly acute; axillary hairs of 4–6 cells. Stem leaves appressed when dry, spreading when moist, imbricate, ovate to ovate-lanceolate, concave, not plicate, 0.4–0.7 mm; base scarcely decurrent; margins entire, subentire to serrulate distally; apex acute to narrowly obtuse; costa to 33–66% leaf length, slender, terminal spine absent; alar cells subquadrate to oblate-quadrate in several rows, little different from more distal cells; laminal cells rhombic to oblong-rhombic, 1.5–3:1, walls thin; proximal cells quadrate to subquadrate, shorter at margins. Branch leaves similar. Sexual condition autoicous; perichaetial leaves erect to flexuose, apex abruptly acuminate. Seta reddish, smooth. Capsule erect, brown, narrowly elliptic to oblong, symmetric; annulus not separating; operculum long-rostrate; peristome without apparent hygroscopic movement, modified; exostome teeth very short, 1/2 endostome length. Calyptra naked. Spores 14–21 µm.


c, e United States, Europe.


Species 1.

Clasmatodon has been variously placed in Fabroniaceae or Myriniaceae, but molecular data strongly suggest a position in Brachytheciaceae as a small, epiphytic, monospecific genus with a reduced peristome.

Selected References