Variation is high in the number of lobes or leaf segments, ranging from 5 to more than 20.

In appearance it is very similar to A. sericeus, but its leaf segments are flat rather than cylindrical.

They create a relatively small, lower surface tentiform mine which is often located under a leaf segment.

The undersides of each leaf segment have one or more sori arranged in chains.

Primary leaf segments have 8-40 small oblong leaflets arranged in opposite pairs.

In larger leaves, it can be found under a folded leaf segment.

The entire leaf segment is held slightly off the ground on support bars of varying length.

Young larvae mine out a fine leaf segment completely, leaving a black, central frass line.

The sori are located within the rolled-under margins of each tiny leaf segment.

The mine consists of a corridor that widens significantly at the end and may occupy an entire leaf segment.