Antitrichia

Bridel

Muscol. Recent., suppl. 4: 136. 1818.

Etymology: Greek anti, opposite, and thrix, hair, alluding to endostome segments opposite exostome teeth
Treatment appears in FNA Volume 28. Treatment on page 591. Mentioned on page 590, 596, 643, 654.

Plants large, in thick mats or deep wefts, yellow-green to dark green, glossy. Stems irregularly branched. Stem leaves ovate-lanceolate to cordate-ovate; base rounded to subcordate, slightly decurrent; margins revolute, serrate, serrulate, or denticulate; apex acute, acuminate, or abruptly acuminate; costa subpercurrent, with 2 or more shorter, supplementary costae at base; alar cells quadrate to transversely elongate, region extending nearly to costa and an equal distance distally; laminal cells smooth; medial cells uniformly linear-flexuose; apical cells oval-rhombic. Branch leaves similar, narrower, smaller, 2–3 × 1 mm; margins more strongly denticulate; apex narrower, flagelliform, smaller; costa weaker. Specialized asexual reproduction absent. Perigonia on secondary stems or sometimes on side branches, leaves deltoid-apiculate. Perichaetia on primary stems, leaves ecostate. Seta short. Capsule exserted, cylindric, oblong-cylindric, or oblong-ovoid; annulus scant or absent, adherent; operculum oblique-rostrate; exostome teeth subulate, trabeculate or papillose; endostome basal membrane absent, segments weakly developed, narrowly subulate, papillose.

Distribution

North America, South America, Europe, Asia, Africa, Atlantic Islands.

Discussion

Species 5 (2 in the flora).

The stems of Antitrichia are densely foliose and internally divided into a strong 4–6-layered cortex of incrassate cells and a medulla of loose, thin-walled cells. The branches are procumbent or pendent, somewhat plumose, and usually elongate, with deltate to subfoliose pseudoparaphyllia investing the branch buds; the central strand is rudimentary or absent. The stem leaves are concave and 2–3 × 1–1.5 mm; the basal laminal cells are rounded-quadrate to elliptic, in a region filling the basalmost angles and extending up most of the margins. The endostome segments are fragile, evanescent, and 1/2–3/4 the exostome teeth length.

Selected References

None.

Key

1 Leaves julaceous when dry; supplementary costae absent or rudimentary, length less than 6 cells; laminal cell walls not or poorly pitted. Antitrichia californica
1 Leaves erectopatent when dry; supplementary costae well developed, length more than 6 cells; laminal cell walls pitted throughout. Antitrichia curtipendula
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