Wikipedia
The Polytrichaceae also known as "Aloe Moss" 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 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.
Usage examples of "polytrichaceae".
In most mosses the teeth are portions of thickened cell-walls but in the Polytrichaceae they are formed of a number of sclerenchymatous cells.
The conducting strands in the leaves show the same tissues as in the central strand of the stem, and in the Polytrichaceae and some other mosses are in continuity with it.
The Polytrichaceae, on the other hand, show a specialization in structure rather than in form.
In the Polytrichaceae another air space separates the spore-sac from the columella.