Micromitrium is a genus of leaf mosses . Micromitrium is included in the Ephemeraceae family Plants scattered in abundant pro-tonemata, green. Stems virtually absent. Leaves erect, linear-lanceolate, rarely with narrow, toothed shoulders, gradually and slenderly acuminate, 1-2 - 0.15-0.26 mm, margins plane, entire or with short single or double teeth distally. Sexual condition synoicous or dioicous. Capsule cleistocarpous or rarely dehiscing by a ring of differentiated cells distal to the equator, yellow- to orange-brown, globose or slightly flattened, slightly apiculate; exothecial cells in 2 layers, stomates numerous and confined to proximal half. Spores fewer than 100, various shapes, proximal face not concave, 50-84 - 40-66 -m, red-brown or dark brown.