Plants robust, ascending from a decumbent base, dark olivaceous. Stems 5-12 cm, repeatedly dichotomous, central strand absent. Leaves loosely appressed when dry, patent to spreading when moist, often becoming secund distally on the stem, lanceolate to ovate-lanceolate, 3-4 × 0.6-0.9 mm, keeled, margins recurved on both sides, awns denticulate, flattened proximally, sometimes decurrent, costa yellowish to pale orange proximally, wider (± 100 µm) near the base, channeled distally, semicircular on abaxial side; basal juxtacostal laminal cells elongate to linear, weakly orange at insertion, nodulose, thick-walled; basal marginal laminal cells in a few rows quadrate to short-rectangular, thick-walled; medial laminal cells quadrate to short-rectangular, strongly sinuose, thin to thick oblique transverse walls and extremely thick lateral walls; distal laminal cells 1-stratose, margins partly 2-stratose. Gemmae absent. Sexual condition dioicous. Seta arcuate, 3-4 mm. Capsule occasionally present, exserted, yellowish green, oblong-ovoid, striate, exothecial cells rather thick-walled, annulus present, operculum rostrate, peristome teeth orange to reddish, perforated, irregularly cleft at apex, nearly smooth basally, papillose distally. Calyptra mitrate.
Grimmia jacutica E. Ignatova, H. Bednarek-Ochyra, O. Afonina & J. Muñoz; G. pachyphylla Leiberg