Montana Field Guide

Plants: Acrocarpous (Vitt 1988), unbranched, growing in open tufts (Crum and Anderson et al. 1981) or mats (Lawton 1971), green, or green with yellow tones (FNA 2014). Fertile stems upright with brown tomentum proximally (Lawton 1971), 20-40 mm tall; infertile stems sometimes reaching 80 mm (FNA 2014), creeping (Lawton 1971), spreading or bent downward (Crum and Anderson et al. 1981).

Leaves: Smaller and more distant below (Crum and Anderson et al. 1981), wavy and somewhat twisted, bent or curved when dry, plane (FNA 2014) and spreading about 45 degrees or more when damp (Crum and Anderson et al. 1981), 3.5-10 mm in length (FNA 2014), 3-4 mm in width (Lawton 1971), often widest in the middle and sometimes rather broad, or occasionally obovate, narrowing to a curved, obtuse leaf tip, or tip sometimes more narrowly-angled, with a mucro or occasionally-toothed cusp; base extending well down the stem; margins flat, sharply- or sometimes dully-dentate from the apex to near the bottom; costa reaching or exceeding the leaf tip (FNA 2014).

Leaf Cells: Marginal teeth 1- to 2-celled, or seldom 3-celled; cells at the leaf edge arranged in 1 layer, long and thin, in 2-4 series; medial laminal cells usually somewhat long, or occasionally with width about the same as length, the cells much smaller near the margins, occurring in up-and-down rows or obliquely-rowed, porose (FNA 2014), firmly- to thickly-walled, the angles thick (Crum and Anderson et al. 1981).

Fruit ripens in the last part of spring (FNA 2014).

The variation of characters within and among populations of Plagiomnium makes identification difficult without fertile plants (FNA 2014).

Damp soil and humus (Elliott and Pipp 2016), and soil overlying stone (Lawton 1971) in wet woods, near watercourses and springs (Crum and Anderson et al. 1981), swamps. Occurring from lowlands to medium altitudes (FNA 2014).

Archegonia and antheridia associating in the same bract cluster. Seta mostly multiple, occasionally to 7 per perichaetium, 20-50 mm tall (FNA 2014), russet proximally, becoming yellow distally (Lawton 1971). Capsule 3-4.5 mm in length, drooping, with an obscure neck (FNA 2014), ochre; stomata in several rows, sunken with guard cells partially hidden; exostome teeth yellow with green tones, papillose; endostome processes ochre, widely perforate with papillose, knobby cilia (Lawton 1971).