Streptanthus anceps, synonyms Caulanthus anceps and Guillenia lemmonii, is a species of flowering plant in the family Brassicaceae,[1] known by the common name Lemmon's mustard.

It can generally be found in areas with alkaline soils.

Streptanthus anceps is an annual herb that produces an erect, waxy-textured stem with lance-shaped leaves borne on petioles.

[3] The inflorescence is a raceme of many fragrant flowers each with four pink-veined lavender petals.

The fruit is a long silique up to 7 centimeters in length.