Montana Field Guide

Plants: Acrocarpous, growing in open to crowded clumps of upright shoots (Flowers 1973). Stems deep russet, mostly 2-5 cm tall, rarely to 7 cm (FNA 2014), mostly unbranched, possessing a central strand; rhizoids brown and tomentose proximally (Lawton 1971).

Leaves: Wavy and a little twisted, curved, or bent when dry (FNA 2014), spreading when wet, 1.3-2 mm in width (Lawton 1971), 2-4 mm in length, the upper leaves much larger (FNA 2014) and more crowded than those below (Crum and Anderson et al. 1981), green to deep green, widely egg-shaped to elliptic, sometimes with ovate tendencies, ending in an acute and sometimes curved or more broadly-angled leaf tip, forming an apiculus or occasionally a small-toothed cusp; base extending a little to well-down the stem; margins flat, becoming russet over time, smooth to slightly dentate in the distal half, seldom toothed further below on the margin, the teeth small and usually single; costa usually reaching or nearly reaching the leaf tip, occasionally shorter, without teeth distally on the upper part of the dorsal surface (FNA 2014), red (Lawton 1971).

Leaf Cells: Margins mostly of 1 cell-layer, seldom with short stretches of 2 layers, the cells long and narrow in up to 3 rows, often becoming somewhat russet with time (FNA 2014), the marginal teeth of 1 cell (Lawton 1971); medial cells of the lamina about as wide as long or, more often, slightly elongated, a little larger toward the center than near the margins, occasionally in somewhat indistinct longitudinal (but not oblique) rows (FNA 2014).

Fruit ripens in the summer (FNA 2014).

Even plants of M. blyttii with smooth-appearing leaf margins should have some leaves that have a few marginal cells with a small bulge at their distal end facing anteriorly, separating them from Rhizomnium and Cinclidium (FNA 2014).

Shaded and damp soil, humus and stone, sometimes on bluffs (FNA 2014); montane (Lawton 1971).

Dioicous. Antheridia with heads plate-like. Perichaetial bracts longer than vegetative leaves. Seta 3-5 cm tall (Lawton 1971), solitary. Capsule sometimes reaching 5 mm in length, ochre (FNA 2014), level to drooping, with a short neck; stomata sunken, with guard cells partly visible (Lawton 1971), occurring in the neck (Crum and Anderson et al. 1981); exostome green with yellow tones (FNA 2014), papillose; endostome segments wide, with cilia in groups of 2-3. Calyptra draping like a hood (Lawton 1971).