The Pottiaceae are a family of mosses. They form the most numerous moss family known, containing nearly 1500 species or more than 10% of the 10,000 to 15,000 moss species known.

Barbula unguiculata, also called as Bird's-claw Beard-moss is a species of moss belonging to the family Pottiaceae. Its color is usually distinctive, a kind of bright yellow-green shared by few simila