Grimmiales

Cushion Pillow Moss ( Grimmia pulvinata )

The Grimmiales are an order of mosses. They are mostly perennial and robust species that form on stones and on rocky dense cushions or lawn. Mostly, they therefore also grow in open, bright locations.

Features

In many species of this order, a transition from the Akrokarpie to Pleurokarpie is observed. The plants then form prostrate to ascending, only slightly branched stems.

The leaves are usually lanceolate with a midrib. Often the leaf ending in a hyaline hair lace. The cells often have thick cell walls. In some species, the cell walls are also thickened irregular knotty. In many species, the leaves consist of two layers of cells.

The sporophyte has a short seta, which is straight or U-shaped bent back into the cushion. The calyptra is large and usually has the shape of a hat. The Sporogon is ovoid to cylindrical. The peristome is haplolepid.

System

The order includes three families

• Grimmiaceae with 10 genera and about 330 species worldwide
• Seligeriaceae with 5 genera and 48 species, mostly temperate latitudes
• Ptychomitriaceae with 5 genera and 62 species, mostly temperate latitudes