Dicranella nicholsii

Dicranella nicholsii R. S. Williams, sp. no v
Plants in brownish-green rather loose mats; stems about 5 mm. high with somewhat distant, spreading, variously curved leaves: stem-leaves, when moist, nearly straight and widely spreading, about 1 mm. long, from an ovate-lanceolate or lanceolate base gradually narrowed to a broad, grooved limb with mostly flat borders somewhat irregularly serrulate nearly one half down, the leaf-blade 2 or 3 cells wide on either side of the costa to the broadly acute apex; costa vanishing a. few cells below the apex, narrow below, 30-40 /j, wide at base; leaf-cells pellucid, distinct to the apex, rather irregularly rectangular, the median ones about 8-10 # wide and 40 /z long, those of the marginal row rather paler, broader, and shorter, forming an indistinct border; perichaetial leaves up to 2.5 mm. long, from an ovate, somewhat clasping base narrowed to a limb one and one half times to twice as long as the ovate part, otherwise very similar to the stem-leaves: seta flexuous, reddish, 8-10 mm. long: capsule short-ovate, about 0.8 mm. long, nodding, curved when dry, not ribbed; exothecal cells short and broad, rather thinwalled, highly convex on the incurved side of the capsule; annulus wanting; lid with a short, stout beak; peristome-teeth reddish-brown, up to 350 p high, mostly divided more than one half down into unequal, slender, papillose forks, # vertically striate below with lamellae on the inner face not very prominent, mostly about 20 ju apart, the basal membrane of three or four rows of darker cells projecting slightly above the mouth of the capsule: spores nearly smooth, up to 1 4 /^ in diameter.
Type collected between New Haven Gap and Vinegar Hill, Jamaica, G. E. Nichols 155 (herb. N. Y. Bot. Gard.).
This species may be distinguished from D. rubra by the flat borders of the leaves, with much wider cells. It is nearest to D. rufescens, but differs in the more spreading leaves, nodding capsule, shorter marginal cells of the leaf and base of the peristome, in which the narrow, smooth cells with thickened walls do not extend well above the mouth of the capsule as in D. rufescens.