The genus name comes from Greek, meaning "unwetted", referring to the fronds' ability to shed water without becoming wet.

They are distinctive in appearance, with dark, often black stipes and rachises, and bright green, often delicately cut leaf tissue.

The sori are borne submarginally, and are covered by reflexed flaps of leaf tissue which resemble indusia.

They generally prefer humus-rich, moist, well-drained sites, ranging from bottomland soils to vertical rock walls.

Species native to North America include A. pedatum (five-fingered fern) and the closely related A. aleuticum, which are distinctive in having a bifurcating frond that radiates pinnae on one side only.