[2] Like most other vittarioid ferns, members of the genus have simple, straplike leaves.

Most species lack a costa (midrib), although a few have a partial one, and the leaves are generally more than 1 centimetre (0.4 in) wide.

The leaves have netlike venation, with three or more rows of areolae ("gaps" in the net of veins) on either side of the midline.

(By comparison, Scoliosorus and Antrophyopsis always have spherical cells at the tips of their paraphyses, and monolete spores.

He included in it several species placed in Hemionitis by Carl Ludwig Willdenow, distinguishing them on the basis of their reticulate, indusiate sori sunken into the leaf tissue.

The name means "growing from a cavity",[4] a reference to the growth of the sori from a groove in the leaf.

[3] Most species occur in tropical Asia and the Pacific, but A. immersum and A. malgassicum are known from Africa and the Indian Ocean.