Bryum argenteum is a bryophyte (moss) that forms very close tufts or cushions; it occurs in patches or is found as scattered individuals mixed with other mosses. Plants are small to medium - sized, 1 - 25 mm long. The stems are julaceous (smoothly cylindrical, like a catkin), 1-25 mm tall, yellowish green or red to red-brown, and branched below. The leaves are crowded and tightly held to the stem, overlapping each other, broadly ovate and concave and green below. The upper surface is hyaline (transparent), usually with a tapering, short point. The sporophytes consist of yellow to reddish brown, short, arched setae, 7-20 mm long and red-brown capsules, 1 - 2 mm long, drooping and wrinkled when dry. The spores are 10 - 15 µm in diameter and finely papillose. The plant is perennial.