Orthotrichum pallens var. parvum

Orthotrichum pallens Bruch var. parvum Ventun,
Hedwigia 12: 21. 1873.
Close to O. tenellum; upper leaves obtuse, crenulate with projecting cells at the apex, the others various; upper leaf-cells reaching about 12 /*; antheridia on a short special branch; seta about 0.5 mm. long; capsules short-obovoid, about 1.5 mm. long, striate when dry and empty; calyptra conic-campanulate, naked; stomata only slightly covered by the surrounding cells, often seemingly almost superficial, at or near the middle of the spore-sac; operculum strongly apiculate.
Type locality: Yellowstone National Park, Wyoming (Roll, as "var. parvum Hedw.").
Distribution: Wyoming and Utah.