Aulacomnium Schwägrichen, 1804, nomen conservandum.

Aulacomnium androgynum, photo by Wilson

Aulacomnium androgynum almost always has "gemmaphores" (erect continuations of the main stems with terminal, globose clusters of elliptical gemmae). Such a feature, unique among local mosses, is found in both species of the genus but A. palustre shows the feature with less regularity. Note that the gemma cup of Tetraphis may be confused with the Aulacomnium gemmaphore, but the Tetraphis structure has the gemmae basally surrounded by modified leaves. One of the valuable signal characters for both species of local Aulacomnium in the field is the glistening, pearly-white, often distally sinuose costa.

Key to Aulacomnium

In this key we treat acrocarpous mosses with serrate to dentate leaves and centrally unipapillose isodiametric median leaf cells. Most specimens have clusters of multicellular gemmae at the ends of specialized gametophytic stalks (gemmaphores).

Species included in this key are all in Aulacomniaceae:
Aulacomnium androgynum (Hedwig) Schwägrichen
Aulacomnium palustre (Hedwig) Schwägrichen

Our two species of Aulacomnium are both very common in their own habitats. Aulacomnium androgynum is a plant of rotten or burned wood and coniferous tree bases, only occasionally petricolous. Aulacomnium palustre is a plant of wet and peaty soil in wetlands.

A. Plant mostly on rotten logs and stumps; erect, microphyllous branches with spherical, apical clusters of fusiform gemmae typically present; basal cells not at all inflated; rhizoid initials in a short-elliptical 1.5-2.5:1 cluster .....Aulacomnium androgynum
A. Plant mostly on soils in bogs; gemmaphores scarce with the gemmae leaf-like; basal cells of leaves more or less inflated; rhizoid initials in a longer cluster .....Aulacomnium palustre