Polytrichaceae
Polytrichaceae is a common family of mosses. Members of this family tend to be larger than other mosses with a thickened central stem and a rhizome. The leaves have a midrib that bears photosynthetic lamellae on the upper surface. Species in this group are dioicous. Another characteristic that identifies them is that they have from 32 to 64 peristome teeth in their sporangium. Classification

Genera

Extinct genera 
 †Eopolytrichum  Cretaceous (Campanian); Gaillard Formation, Georgia, USA 
 †Meantoinea  Cretaceous (Valanginian); Apple Bay locality, Vancouver Island, British Columbia, Canada
 †Polytrichites  Miocene; Latah Formation, Washington, USA

References 

 
Moss families