Montana Field Guide

Plants: Acrocarpous (Vitt 1988). Growing in crowded patches of erect shoots, green with yellow or red tones, turning to russet with time. Stems mostly 20-40 mm tall, seldom to 60 mm (FNA 2014), occasionally few-branched (Crum & Anderson et al. 1981), with leaves a little more dense at the top of the stem, frequently with numerous long rhizoids, especially near the terminal ends of the stems (FNA 2014).

Leaves: Somewhat distantly spaced below, more dense above (Crum & Anderson et al. 1981), green, or green with yellow or red tones, turning a dull, rusty red over time, twisted and curved when dry, upright or spreading a little when wet, mostly 2-4 mm in length, egg-shaped, plane to faintly cupped, scarcely enlarged at the top of the stem (FNA 2014); apex acute and frequently with a stout tip (Crum & Anderson et al. 1981); base narrowly and strongly extending down the stem; margins tightly rolled back and under proximally, sometimes over half the leaf length, the border strong; costa extending slightly beyond the leaf tip (FNA 2014), red below to somewhat russet above (Crum & Anderson et al. 1981).

Leaf Cells: Border of 2-3 cell rows, unistratose; medial and upper laminal cells diamond-shaped (FNA 2014) to 6-sided (Crum & Anderson et al. 1981) with moderate to thick walls, 3:1 or shorter, narrower to as wide as the lower laminal cells; lower laminal cells quadrangular and short, 3:1 (FNA 2014).

Fruit ripens spring through mid-autumn (FNA 2014).

The related Ptychostomum bimum is not as large as B. pseudotriquetrum, is synoicous rather than dioicous, and has less substantial decurrencies (FNA 2014).

Mineral-rich, wet soil and humus, edges of wooded swamps, lakes, and sedge fens, occasionally on wet shelves and seeping bluffs, and edges of foliage mats on rocks (Crum & Anderson et al. 1981).

Dioicous. Seta mostly 10-40 mm tall. Capsule somewhat long and egg-shaped (FNA 2014) to club-shaped, inclined to drooping (Crum & Anderson et al. 1981), 3-5 mm in length, brown, the opening yellow (FNA 2014), the neck occasionally the same length as the rest of the capsule (Crum & Anderson et al. 1981); peristome fully developed; exostome dentitions yellow below, transparent above, without pores on the center line; endostome divisions with egg-shaped openings; cilia tall and transversely ridged (FNA 2014).

Specialized vegetative reproduction sometimes occurring by brown, filiform gemmae produced in the leaf axils (FNA 2014).