The flower and the fruit of an individual plant are generally needed to identify the specific variety.

Varieties are largely limited to marginal habitats such as disturbed sites in the arid regions of the continent.

The group also contains a number of edaphic specialists which occur at desert seeps, which frequently exhibit high levels of calcium carbonate.

Astragalus lentiginosus is a perennial or occasionally annual herb with leaves up to 15 centimetres (5.9 inches) long divided into many pairs of small leaflets.

The pod dries to a papery texture and dehisces starting at the beak to release the seeds.

The epithet lentiginosus refers to the red mottling commonly found on the pods which resemble freckles.