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Polytrichum commune

Polytrichum is the genus commonly known as the "Hair Cap Moss." Polytrichum commune is also commonly known as "Common Hair Cap Moss." These mosses are commonly referred by this name because the sporophyte has distinct hairs protruding from the calyptra. A member of the order Polytricales, the common hair cap moss is found throughout the world in moist areas, cosmopolitan areas, wet moorlands, bogs, swampy woodlands, coniferous forests, and boreal forests. This genus is moderately pollution tolerant. Polytrichum commune is generally dark green, robust, 4-20 centimeters tall. The lower portion is covered by gray rhizoids, and these mosses are single sexed. The males have enlarged heads at the tips of the plant, and the females produce the sporophytes.


The leaves of Polytrichum commune are lance shaped, sharply pointed, and 6-10 mm long. The stems slightly rigid to erect with pointed leaves arranged spirally at right angles around the stem creating a star-like appearance from above. The leaves have a membranous, sheathing base, and are coarsely toothed. The costa of the leaves is covered in 20-55 vertical tiers of photosynthetic lamellae that are 4-9 cells high each. Each tier ends in a U-shaped cell. The lamellae create a microenvironment for microscopic organisms such as fungi and rotifers (Silverside 1998).


The sporophytes are common at the tips. The stalk is wiry, and very long reaching 20-30 cm at times (Silverside 1998). The capsules are horizontally 4 sided. The capsule contains 64 short, rounded, peristome teeth with an expanded central membrane around the capsules mouth. The calyptra has a tuft of hair at the tip and it covers the entire capsule.


This genus has been used as decorative material on New Zealand Maori cloaks. On several cloaks, the clusters of moss occurring on the outside face are woven into the fabric. In others, the entire face of the fabric is covered with dense, leafy, moss shoots. They are thought to provide extra insulation and decoration. Teas made from this genus of moss have been taken to relieve and dissolve gall bladder and kidney stones. A strong tea of common hair cap mosses was used as a rinse in women’s hair to strengthen and beautify ladies tresses. The leaves have been used to make brooms and brushes. The leaves have also been woven or plaited into mats, rugs, baskets, and hassocks. One hair cap moss basket from a Roman fort in Newstead, England dates back to 86 AD.


  1. Crum, Howard, 1983, Mosses of the Great Lakes Forest, pgs.371-377, U. of Michigan.
  2. Hale, Alan, http://home.clara.net/adhale/bryos/pcommune.htm

Written by Angelo Giallombardo
May 2001

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