Genus PleuridiumThe plants of the Genus Pleuridium are minute and erect with simple or branching stems clustered to form dense cushions on the ground.
The leaves are small and few below, but longer and crowded above; they are oval at the base, tapering to a long awl-like point with a broad vein forming most of the apex.
The spore-cases are solitary and terminal, immersed on a short pedicel. They are almost spherical with a point on the summit and a persistent columella.
There are thirty-six species known in all, five in the United States.
The generic name Pleuridium is derived from the Greek; at the side. The name is suggestive of the position of the spore-cases, which in some species appear to be on the sides of the stems instead of on the summits, because a side branch has grown from near the base of the spore-case -but in the same direction as the main stem- leaving the spore-case behind.
Pleuridium Subulatum Moss