Orthotrichum citrinum Sullivant & Lesquereux; O. ohioense var. citrinum (Sullivant & Lesquereux) Lesquereux & James

Plants 0.4-1.4 cm. Stem leaves stiff, loosely erect-appressed when dry, narrowly lanceolate to oblong-lanceolate, 1.4-2.9 mm; margins strongly revolute to just before apex, entire; apex obtuse to bluntly acute, ; basal laminal cells subquadrate to short-rectangular, walls thin, not nodose; distal cells 8-10 µm, 1-stratose, , papillae 1-2 per cell, conic, low. Specialized asexual reproduction absent. Sexual condition gonioautoicous. <Vaginula with hairs absent>. Seta to 1 mm. Capsule emergent, oblong to ovate, 1-1.5 mm, 8-ribbed almost to base, , not constricted below mouth; stomata immersed, ; peristome double; prostome absent; exostome teeth 8, splitting to 16 with age, reflexed, finely and densely papillose; endostome often absent, or segments 8, well developed, of 1 row of cells, smooth. Calyptra oblong, smooth, naked or slightly hairy, hairs smooth. Spores 15-19 µm.

Deciduous trees in mesic hardwood forests, along streams; low to moderate elevations (100-1000 m); N.B., N.S., Ont., Que.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Ky., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Vt., Va., W.Va.

Orthotrichum ohioense is distinguished by the 16 exostome teeth, eight rudimentary endostome segments, slightly 8-ribbed ovate capsules, leaves that are lanceolate and bluntly acute at the apices, and laminal cells smaller than 10 µm.