With erect stems and slender upper branches reaching 4–6-feet tall, this airy mustard has showy clusters of white flowers on the branch tips and numerous long, thin seed pods. Note the stamens with purplish anthers extend beyond the throat and are as long as the petals.

FLOWER: March–October. Dense  cylindrical, spike-like cluster of white to purple-tinted flowers with 4 spreading, oval petals, each 1/8–5/16-inch long (4–8 mm), and 4 similar, spreading, petal-like sepals; stamens and style extend outside the throat; 6 stamens of equal length, anther tips slightly hooked. Fruit pods (siliques) are 2–3-inches long (5–7 cm) and slender (1 mm), held horizontal or drooping, constricted between seeds.

LEAVES: Basal leaves with long stems (petioles) and lance-shaped blades 3 1/2–9-inches long (9–23 cm), margins with lobes along midrib. Stem leaves alternate. Lower blades have short stems (petioles), and become nearly stemless (sessile) near the flower cluster. Stem blades lance-shaped to linear 1 3/8–3 3/8-inches long (3.5–8.5 cm); margins toothed, sometimes lobed, becoming entire on upper stem.

HABITAT: Sandy, gravelly soils, moist canyons, hillsides, roadsides; pinyon-juniper, ponderosa-oak woodlands.

ELEVATION: 4,900–8,700 feet.

RANGE: AZ, CO, NM, TX, UT.

SIMILAR SPECIES: 4 species in NM. Texas Thelypody, T. texanum, in se quarter of NM, branches from the base and has lobed upper leaves and spreading pods constricted between pods; Entire-leaf Thelypody, T. integrifolium, in northern NM brushlands, has stem leaves with no stems (sessile) and pods constricted between seeds; Loose-flowered Thelypody, T. laxiflorum, in the Four Corners, has pinkish flowers, stem leaves with short stems (petioles), and pods spreading to drooping and constricted between seeds.

NM COUNTIES: Widespread except eastern plains in low- to mid-elevation, moist habitats: Bernalillo, Catron, Cibola, Colfax, Dona Ana, Eddy, Grant, Guadalupe, Harding, Hidalgo, Lincoln, Los Alamos, Luna, McKinley, Mora, Otero, Rio Arriba, San Miguel, Sandoval, Santa Fe, Sierra, Socorro, Taos, Torrance, Union.