Montana Field Guide

Plants: Acrocarpous (Vitt 1988). Growing in deep green or, more frequently, ochre-colored tufts (Crum and Anderson et al. 1981) or crowded cushions. Stems upright with ascending branches, 20-50 mm in height (FNA 2014).

Leaves: Irregularly bent and spiraled when dry, expanding outwardly when wet, lance-shaped and linear, 1.5-3 mm in length; margins flat (FNA 2014), or occasionally turned back and under (Smith 1980), frequently somewhat toothed (Crum and Anderson et al. 1981) or, near the apex, wavy from papillae (Smith 1980); apex narrowly tipped (FNA 2014); costa reaching the tip or extending beyond it slightly (FNA 2014).

Leaf Cells: Proximal laminal cells with thickset walls, hyaline, rectangular; marginal laminal cells similar to the basal cells; cells above 6-sided and a little rounded (Smith 1980), partially concealed by tiny, lens-shaped papillae (FNA 2014) arranged in rows (“longitudinal striae”) (Crum and Anderson et al. 1981).

The papillae of A. mougeotii are tiny, elliptic, and only partially conceal the upper cells, whereas the papillae of A. lapponicum are “warty,” large and conspicuous. The laminal cells of A. lapponicum are larger as well (FNA 2014).

Seasonally wet, seepy, shaded basic stones (Smith 1980), sandstone and granite, and in seepy, sheltered fissures of vertical faces, and close to waterfalls (Crum and Anderson et al. 1981). From low to high elevations (FNA 2014).

Dioicous. Perichaetial leaves bigger than stem leaves, lengthened and slender, long-tipped; base enveloping the stem somewhat. Seta 2.2-3.5 mm in length. Capsule protruding beyond perichaetial leaves just slightly, 1-1.5 mm in length (FNA 2014), pleated when dry and old (Smith 1980), 8-ridged, contracted slightly under the mouth; peristome lacking (FNA 2014).