Hypnum cupressiforme Hedw.

Exceedingly variable even in one tuft, but much more so from different sites; this could easily make ten or more herbarium species by selecting types, but all these have features in common, and the field bryologist finds they all grade into one another, so that specific separation is impossible without having connecting links all through. It is dioecious and seldom fertile; it is usually pinnate, seldom 2-pinnate, and in the stronger forms the branch tips are uncinate. The most common cosmopolitan form, a shining, greenish-yellow plant growing in dense intricate mats usually upon stones or soil, varying from a close prostrate habit to an inch depth and fairly lax, and though pinnate on every fork it often has so many forks as lower branches as to appear 2-pinnate. Branches sometimes blunt, sometimes tapering to a point. Leaves oblong-lanceolate-falcate, 2 mm long, smooth, concave, with erect margins, not plicate, often strongly uncinate, and though produced all round the stem they often part in the middle on the upper side so as to appear distichous in two rows on that surface, while the under surface is a confused mass of leaf-points. Nerve absent or usually so (double and short when visible); margin erect, practically entire; cells vermicular, and shining above; alar cells abundant and mostly small, in flattened out but hardly auriculate angles; leaf-base wide. Perichaetal leaves sheathing and acuminate, the inner erect and clasping, the lower spreading. Seta 1 inch long, red, smooth; capsule inclined and curved, red, cylindrical, with short, acute, conical beak, white smooth calyptra, and complete peristome. Common everywhere.