Toothed phascum moss is a very small moss that is common in the grasslands around Kamloops. It’s scientific name use to be Phascum cuspidatum but it has recently been changed to Tortula acaulon. It’s a widespread species that is found in most provinces and states in North America. Plants occur singly or in small clumps and consist of a few leaves that surround large globose capsules that are borne on very short stalks. The plants are only a few millimeters tall. They generally occur in disturbed areas on minerals soil.

The leaves are long and narrow with a midrib that extends past the tip of the leaf. Like most moss leaves, the leaves are only one-cell thick. Most of the leaf cells contain several green chloroplasts that function in photosynthesis. Most cells are more or less square in outline with somewhat thick cell walls.

Cells near the base of the leaf are larger and longer and lack chloroplasts.

Unlike most mosses, the capsules of toothed phascum moss does not have a capsule lid and peristome teeth that aid in spore dispersal into passing air currents. Instead, the spores are released after the capsule matures and eventually decays allowing the spores to be released.