Montana Field Guide

Plants: Acrocarpous, growing in open to crowded clumps of erect shoots (FNA 2007), sometimes well-scattered (Lawton 1971), green with yellow tones above, somewhat ochre or brown below. Stems mostly single, sometimes reaching 10 mm in height, possessing a central strand; rhizoids occurring at the bottom of the stem (FNA 2007).

Leaves: Generally upright or spreading to about 45 degrees (FNA 2007), sometimes tending to point toward the same side of the stem (Lawton 1971), the somewhat egg-shaped base steadily narrowing to a subula, the subula long and with a longitudinal groove; margins flat (FNA 2007) or curved up and inward, sometimes slightly dentate distally but otherwise smooth; costa extending to the apex or beyond (Lawton 1971), largely filling the subula (FNA 2007).

Leaf Cells: Lamina 2 cell-layers thick above; distal laminal and subular cells somewhat long and quadrangular, becoming longer near the bottom of the leaf, occasionally papillose and more often near the leaf tip; margins 2 cell-layers thick in the upper half, 1-layered below; costa in X-section with guide cells in 1 row, a weak ventral stereid band and a well-defined dorsal stereid band (FNA 2007).

Fruit ripens in early- to mid-summer (FNA 2007).

The similar Ditrichum flexicaule often can be distinguished by its marginal cells near mid-leaf, which are isodiametric or nearly so, or lengthened crosswise to the leaf. Those of D. heteromallum are long (Lawton 1971).

Damp (Elliott & Pipp, 2016), often disrupted, bare, or finely- to coarsely-textured soil and gravel on embankments, roadsides, open spaces in woods (FNA 2007). Ranging in elevation from low-lying areas to occasionally over 4920 feet (Lawton 1971).

Dioicous. Perichaetial leaves enveloping the stem (Lawton 1971). Seta, russet, 1-2.5 mm in height, carrying the capsule beyond the perichaetial leaves. Capsule upright, russet, 0.5-1.5 mm in length (FNA 2007), straight, frequently the mouth smaller in diameter (Lawton 1971); peristome single, the 16 teeth (FNA 2007) 2-fid and split almost to the base (Lawton 1971), weakly papillose, light orange. Calyptra draping like a hood (FNA 2007).

Specialized vegetative reproduction occurring rarely from tubers produced by the rhizoids, the tubers looking short and filamentous with enlarged, deformed rhizoid cells (FNA 2007).