Funaria hygrometrica is one of the most common, weedy, and widely distributed mosses in the world; its distribution closely parallels that of Bryum argenteum. It is widely illustrated in textbooks to demonstrate the life cycle of a typical moss, possibly because of the abundant conspicuous sporophytes produced and its frequent presence in greenhouses. However, the peristome with opposite, instead of alternate, teeth in the two peristome rows is clearly atypical among the majority of mosses. Most of the varieties that have been described probably do not merit recognition because of the morphological plasticity of the species in response to environmental conditions.