Platydictya Berkeley, 1863.

Our single species of Platydictya is easily recognized in the field simply by its extremely small size and its pleurocarpous growth form. Microscopic features useful in identification include a leaf fewer than ten cells long with those cells rather short elliptic. The leaf margin is completely entire, and there is no costa, not even a short double one. One might confuse this plant under the microscope with extremely small examples of Amblystegium serpens or A. juratzkanum, but these latter mosses have a short costa, and they have quadrate to rectangular cells in a well demarcated alar region.
see Keys to Hypnum, Amblystegium Etc.

Species included:
Platydictya jungermannioides (Bridel) H. Crum