Species description:
Species name presumably in reference to its common occurrence.

Reproduction:
Sporophytes common, seta red-brown and wiry, calyptra whitish to light brown, sporangium erect until mature, then inclined. Sporangia maturing in summer.

Distinguishing characteristics:
The toothed leaves with many lamellae on the upper surface, the sheathing leaf bases, the angular sporangia, when mature, and the generally large size (up to 200 mm or more long) usually separate this species

Habit:
Forming dense, tall, dark green turfs 50-500 mm tall, in which the leaves are strongly divergent from sheathing bases when hu­mid, becoming incurved to somewhat contorted when dry.

Similar Species:
From P. juniperinum and P. piliferum, P. commune is readily distinguished on the basis of its toothed leaf margins (teeth are lacking the first two species). From P. alpinum, the most useful charac­ter is the sporangium angled in P. commune and not angled in P. al­pinum. From P. formosum, a species of forested habitats, P. commune differs in its more obvious shiny sheathing bases of the leaves. In P. formosum, the sporangia contract conspicuously below the mouth when dry and the mouth flares outward; in P. commune this is not apparent. Young mature sporangia of P. formosum are greenish to pale brown; those in P. commune are brown. In P. Iyallii, the sporangium tapers to the mouth and usually has only one longitudinal ridge; that of P. com­mune is four-angled in cross section and has four longitudinal ridges. Comments: P. commune was used to make mattresses in early times. The stems, stripped of leaves, were also bound together to make brooms. An infusion made of this moss has been used as a hair restorative but there is no evidence that it is effective. Small rodents and birds often consume the sporangia. Commonly called hair -cap moss or pigeon wheat.

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration Source:  Some Common Mosses of BC

Synonyms and Alternate Names:
Polytrichum commune var. maximoviczii Lindb.
Polytrichum commune var. nigrescens Warnst.
Polytrichum commune var. uliginosum Wallr.