Plagiomnium cuspidatum (Hedw.) T. Kop.

Plagiomnium cuspidatum stems grow both horizontally and vertically, generally the vertical stems  give rise to the sporophytes. The leaves appear to be shaped like elongated ovals with a protruding tooth at the apex. The costa of the leaf is noticeable and the leaves have teeth from approximately the middle of the leaf to the apex. leaves appear to come off of opposite sides of the stems except for the tips of the shoots that bear sporophytes. This moss can be found in moist to wet habitats growing a variety of substrates. The peristome teeth are yellow.

Compared to:

Plagiomnium ciliare–  Teeth run from the base to the apex along the margins of the leaves. Stems are often taller.