Species: Thelypodium sagittatum ssp. sagittatum

Slender Thelypody is an herbaceous biennial or short-lived perennial with solitary, simple or branched stems that are 3-8 dm high and arising from a taproot. The lower leaves are 6-20 cm long and have petioles and broadly lance-shaped, entire-margined blades. The upper leaves are smaller, narrowly arrow-shaped, and they lack petioles. Foliage is glabrous or nearly so and has a thin, waxy coating. Flowers are densely clustered on ascending stalks in cylindric inflorescences that expand greatly when in fruit. Each flower has 4 separate sepals that are 3-7 mm long, 4 separate, lavendar petals that are 7-14 mm long and 1-3 mm wide, and 4 long and 2 short stamens. The ascending, straight, cylindric siliques are 18-53 mm long and less than 1 mm wide.