Astragalus lentiginosus var. fremontii is the larval food plant of Glaucopsyche lygdamus deserticola. According to Jepson, it's a plant that prefers open sandy flats and gravel between 400 to 2900 m. elevation. It is in southern California and southern Nevada, and it is common at the type locality of deserticola in Cottonwood Pass, NV.

Astragalus lentiginosus var. fremontii flowers.

Leaves are between 3 and 12 cm.