Haircap moss Polytrichum sp. It is nice to lie down on haircap moss and take a nap. In the old days, the Sámi used to cut a piece of this moss that was their size; thus, they got a sleeping pad for themselves. In Finland, there are six haircap moss species; the most common one is the common haircap (Polytrichum commune). In appearance, haircaps look a little like pine shoots. The leaves are stiff and resemble needles. Haircaps grow into wide mats and up to half a metre in height. They are not very demanding as concerns their habitat, but the common haircap thrives in wet environments.