Orthotrichum cancellatum Cardot & Thériot
Plants 0.5--3 cm. Stem leaves loosely erect-appressed and often slightly contorted when dry, narrowly lanceolate to oblong-lanceolate, 2--3.6 mm, sharply acute or bluntly acuminate; margins revolute to near apex, entire; distal laminal cells 7--14 µm wide, 1-stratose, with 2--3 conical papillae per cell; basal laminal cells elongate-rectangular, nodose. Sexual condition goniautoicous. Seta 0.5--1.6 mm. Capsule usually 1/2--2/3 emergent, sometimes immersed or fully exserted; urn oblong to oblong-cylindric, 0.8--1.5 mm, strongly 8-ribbed 1/2--2/3 length; stomates superficial; peristome double; endostome segments 8, 1--2 rows of cells, smooth or finely verrucose; exostome teeth 8, reflexed, reticulately papillose to obscurely papillose. Calyptra oblong-conic, sparsely hairy, hairs smooth or with small papillae. Spores 19--29 µm.
In the Great Lakes region usually on trunks of both deciduous and coniferous trees, rarely on boulders in hardwood forests, in the Arctic it is usually found on small trees; 0--1000 m; Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que.; Alaska, Maine, Mass., Mich., Minn., N.H., N.J., N.Y., Pa., Vt., Wis.; n Asia.
This species is distinguished by having oblong capsules with exostome teeth perforate almost to the base and cancellate in the distal portions.