Montana Field Guide

Plants: Pleurocarpous, growing in slender, widely-spreading mats, deeply olivaceous or seldom green with yellow tones. Stems hugging the substrate, freely branched, the branches distant and appressed; paraphyllia not present; rhizoids borne in groups on leaves near the leaf attachment (FNA 2014).

Leaves: Hugging the stem to upright when dry, spreading to about 45 degrees when damp, 0.4-1.2 mm in length, about twice as long as wide or a little less, cupped, not pleated, egg-shaped, the base spreading, narrowing above to an acumen, the acumen occasionally curved in sickle-like fashion and without a hair-point; leaf edges flat or seldom curved back and downward below; costa typically but not always double, occasionally absent, extending less than halfway up the leaf. Branch leaves smaller than stem leaves, egg-shaped to nearly round. Leaves of stoloniferous stems widely egg-shaped to nearly round (FNA 2014).

Leaf Cells: Stem leaves with lower laminal cells isodiametric to twice as long as wide; medial cells with length similar to width or to 3 times longer, smooth, the walls of medium thickness; alar cells square to short and oblong, only slightly distinct from adjacent cells. Branch leaf medial cells typically not as long as those of the stem leaf (FNA 2014).

Fruit ripens in summer (FNA 2014).

In shaded areas on basic stone, wood, and bottoms of trees, the mats sometimes fully adorning vertical faces of protected boulders and hanging over bluff edges. Ranging from lowlands to alpine elevations (FNA 2014).

Dioicous. Seta 1-2 mm tall, russet. Capsule slanted, 1.5-3 mm in length; exostome teeth lance-shaped and sometimes very slender, with delicate, horizontal lines; endostome processes slender; cilia present (FNA 2014).