E-Flora BC: Electronic Atlas of the Flora of British Columbia

Species description:
Genus name meaning split tooth, referring to the forked peri­stome teeth. Species name based on the fancied resemblance of the moss to the fern Adiantum.

Reproduction:
Sporophytes dark brown when ripe, peristome bright red-brown, occasional but, when present, abundant in that population, maturing in spring.

Distinguishing characteristics:
The curious leaves with the unique flap immediately indicate this genus. The species shows pronounced teeth on the leaf margins and the plants tend to be soft with leaf points that curl downward when dry.

Habit:
Forming short to tall turfs of erect to suberect conspicuously flattened, dark green to light green plants.

Similar Species:
F. osmundioides is similar, but is half the size and usu­ally forms very dense turfs; F. grandifrons is of similar size but the plants are aquatic and essentially opaque and very dark green while F. adianthoide leaves are translucent and the plants are not aquatic.