Montana Field Guide

Plants: Stems flaccid, long (120 x 6 mm), and highly branched. Yellow-green to dark green, sometimes becoming brown to black, especially in older sections.

Leaves: Leaves paired, lanceolate to linear-lanceolate and commonly slightly falcate, and up to 7.0 x 0.6 mm. Leaves usually 10 or more times as long as wide. Apex acute. Vaginant lamina about 1/3 to 1/2 the length of leaf. Dorsal lamina often ends before the base of leaf.

Leaf Cells: Laminal cells of 1-layer and smooth, but sometimes are 2-layered near costa. Median cells above the vaginant leaf are quadrate to hexagonal, thick-walled and slightly bulging, and become larger towards the costa. Margin entire with no border. Basal cells rectangular. Costa ends 15-35 cells before the apex.

When dry the leaves are fragile. Plants are often encrusted with diatoms. Could be confused with F. grandifrons which occurs in flowing water, but has pluristratose laminal cells. Because of their vaginant leaf, Fissidens are often confused for liverworts, particularly Diplophyllum.

Aquatic, attached to rocks, soil, and other substrates in flowing and stagnant waters and in coastal estuaries.

Seta 0.5-0.6 mm tall. Capsules are lateral, straight, erect, ovoid to cylindric, somewhat contracted under the mouth when dry, and 0.5-0.6 mm long. Calyptra smooth. Autoicous.

Perigonia and perichaetia on short (sometimes long) axillary branches, are 1-5 per leaf axil, and are inconspicuous.