The Acmispon glaber stems are green, erect, somewhat branched, with small, deciduous, pinnate leaves consisting of three to six leaflets. The plant blooms from about March to August and has flowers that are bilateral, small (7–11 mm), yellow, and clustered together in an inflorescence consisting of two to seven flowers in the upper leaf axils. The flowers become reddish with age. The fruit consists of a curved legume with two seeds.

Acmispon glaber is a food consumed by numerous wildlife, providing intake for hummingbirds, bees, butterfly larvae, and deer.^[2] Among the larvae are the Acmon blue, Afranius duskywing, Avalon scrub hairstreak, bramble hairstreak, funereal duskywing, and northern cloudywing.^[3] Common plant associates in chaparral, especially in the transition between coastal chaparral and coastal sage scrub, include California sagebrush and toyon.^[4]

Landowners seeking to provide a home for reintroducing the Palos Verdes blue butterfly have been required to have sufficient Acmispon glaber plants to provide the butterflies with shelter.^[5]

Adult Acmispon glaber plants are usually killed by fire due to their thin epidermis and broom-like foliage that burns easily, but the seeds of Acmispon glaber are scarified by fire and readily germinate in the first rainy season after a fire. For 2 to 3 years after a fire in a sage scrub habitat, the flora consists primarily of herbaceous annuals and short-lived herbaceous perennials, but after the first 2–3 years, Acmispon glaber generally becomes dominant, being gradually replaced by long-lived shrubs after 5–10 years post-fire.^[6]

Due to their seeds' fire adaptation, Acmispon glaber benefits from heat scarification in cultivation. Heat treatment significantly increases germination rate.^[6]

• Acmispon glaber var. brevialatus is endemic to California.

• USDA: Lotus scoparius
• Jepson Flora Project: Lotus scoparius
• Lotus scoparius - U.C. Photo Gallery