Green spleenwort is a fern with a single, 0.5-1mm long sori, elongate, that follows the straight or slightly curved veins on the abaxial surface of the laminae. Indusia are thin, whitish, entire, and often deciduous. Rachis is 4cm long, reddish brown at base, and greenish above. It has numerous, linear-oblong, bluntly lobed, pinnate fronds that are 5-15cm long and 1.5cm wide, 9-16 pairs of pinnae that are opposite at base, but alternate toward the middle of frond and above. Its stems are short-creeping or ascending and frequently branched. Scales are linear, blackish, and strongly clathrate (lattice-like in appearance). Stipes are 1-6cm long, entirely exalate, reddish-brown at the base, and greenish above.
It can be distinguished from A trichomanes by its rachis, which is reddish brown only at the base and greenish above (vs reddish brown throughout) and its pinnae, which are more widely spaced toward the base of the blade.