H. heimii is a widely distributed moss of both Northern and Southern hemispheres. A largely coastal moss, it occurs in turfs with stems c.1 cm high. The leaves are oblong to lance-shaped and toothed toward the apex. The upper leaf cells are papillose (with protuberances). The 1-2mm long capsules are brown and oblong, lack a peristome and are borne on a 1 to 1.5 cm long stalk.