Mountain pincushion (Dicranoweisia crispula) is a very common moss  usually found at higher elevations as small round cushions on boulders. When dry, the leaves are twisted and contorted.

Mountain pincushion with twisted and contorted leaves

Mountain pincushion is very similar to the other species “Common Pincushion” that also belongs to the same genus but has a different species name – Dicranoweisia cirrata. The easiest way to tell them apart is that mountain pincushion is much more common and almost always grows on rock whereas common pincushion grows on tree trunks. Unlike many other species that grow on rock, mountain pincushion leaves do not have the white hairtip points that are so common in species that grow on rock.

Common pincushion growing on a tree trunk

Both species are often distinguished from other mosses that have twisted and contorted leaves in that the capsules are erect rather than bent at an angle or hang downwards like those of most species of mosses. Fortunately, capsules are frequently produced by both species and are often a reliable field character.

Common pincushion capsules.

As with most mosses, mountain pincushion have leaves that are one-cell thick. The leaf cells are short rectangular cells with relatively thick cell walls. Mountain pincushion is distinguished from common pincushion and many other mosses by having cuticular ridges that occur on the leaf cells. These appear as semitransparent lines that run along the surface of adjacent leaf cells.

Cuticular ridges on leaf cells of Mountain pincushion