Orthotrichum Moss

Orthotrichum exiguum Sull. Musci U. S. 33. 1856
Plants small, less than 5 mm. high, dark green; leaves appressed when dry, oblong, the lower smaller and subacute, the upper and the perichaetial much larger and obtuse, reaching 1 mm, in length, the margins more or less reflexed, especially below; costa strong, reaching nearly or quite to the apex; upper leaf-cells rather irregularly rounded, isodiametric, 7-10 n in diameter, very dense above, papillose-mammillose, the papillae nearly as large as the cell and sometimes slightly notched, the lower cells becoming gradually elongate and smooth toward the base, oblong-rectangular at the insertion; dioicous; seta very short; capsules nearly or quite immersed, oblong-ovoid with a short, broad neck, about 1 mm. long, obscurely ribbed when dry; calyptra nearly or quite naked; exothecial cells not differentiated; stomata on the neck, superficial; operculum hemispheric-apiculate ; peristome-teeth united in pairs, irregularly substriate, the segments 8, broader than the paired teeth and nearly as long, punctate; spores maturing in spring.
Type locality: Base of trees, Santee Canal (RavenelT). Distribution : Very rare ; Norfolk, Virginia ; Georgia.