Description from TN Native Tree & Plant Nursery
Leucobryum, commonly called white moss or cushion moss, can be found growing wild worldwide, and is quickly made its way into residential gardens as ground cover and decorative touches. This simple to care for moss can be easily added to a moss aquarium also.
Cushion moss leucoloryum, gets its name from its interesting growth pattern. Unlike many mosses, cushion moss grows in a humping pattern. This pattern can resemble a pin cushion. It is also known as white moss because it has a silvery white look when dry that turn to a rich green color when wet. This moss ball appearance is what makes it so attractive in mass gardens.