Rhizome creeping or erect,
terrestrial or epiphytic fern, covered with small dark and clathrate, scales.
Stipe cointaining two vascular strands at the base, these uniting upwards into
a 4-armed strand. Fronds simple, pinnate
or more finely dissected to tri-pinnate, with free veins. In the finely
disected fronds, one vein and one sorus to each lobe of its leaflets. Sorus
long, on the side of the veins, protected by narrow indusium, in some species
double sori, or sori of irregular orientation may occur.