Montana Field Guide

Plants: Acrocarpous, growing in small crowded carpets or cushions, green with yellow tones to a deep olive green, with a whitish or greyish cast from hyaline awns. Stems 0.5-2 cm in height, the branches few (FNA 2007).

Leaves: Closely spaced, overlapping and lying close to the stem near the stem apex (FNA 2007), sometimes spreading a little when dry (Crum & Anderson et al., 1981), curved back and downward, and sometimes spreading to 90 degrees in the lower part of the stem, 0.6-1.2 mm in length (minus the awn), strongly cupped (Flowers 1973), egg-shaped with the broad end either proximal or distal, tapering to an acumen or acute leaf tip (FNA 2007), the leaves progressively longer toward the stem apex; awn nearly smooth to finely saw-toothed, longer in the upper leaves (Crum & Anderson et al., 1981), 0.3-1.4 mm in length (FNA 2007); margins flat, smooth, or sometimes a little toothed above (Flowers 1973); costa ending in the awn’s base (Crum & Anderson et al., 1981), in X-section convex on the dorsal leaf face, grooved ventrally (Flowers 1973).

Leaf Cells: Lamina 1 cell-layer thick above, seldom with ridges of 2 layers above; upper and medial laminal cells about as broad as long, or somewhat elliptic or oddly diamond-shaped, the medial cells a little shorter than the upper cells (FNA 2007); lower laminal cells green, quadrangular, becoming nearly square near the leaf edge (Crum & Anderson et al., 1981); margins 1 cell-layer thick (Flowers 1973); costa in X-section conspicuously folded longitudinally (FNA 2007).

Fruit ripens in spring and summer, influenced by the elevation (FNA 2007).

J. raui tends to occur in cooler, slightly moister areas than its close relative, J. wrightii, more often inhabiting higher elevations and not extending as far south. J. wrightii has a costa flat ventrally in X-section rather than distinctly longitudinally folded, and the lower leaves usually lie flat against the stem rather than spreading (FNA 2007).

Autoicous. Perichaetial awns sometimes reaching 1.7 mm in length, the lamina to 1.5 mm in length. Seta short, ca 0.5 mm tall, leaving the capsule hidden amongst the bracts. Capsule 0.8-1 mm in length, ochre, becoming russet over time; operculum ca 0.5 mm (FNA 2007); peristome pale brown (Crum & Anderson et al., 1981). Calyptra bell-shaped, its base occasionally lobed or a little torn-looking, shielding ca 3/4 of the capsule (FNA 2007), stramineous with a red apex (Flowers 1973).