Spreading by rhizomes with stems 7 3/4–40-inches tall, this milkweed has whorls of thin, linear leaves and clusters of white flowers. Note the dwarf lateral shoots in some of the leaf axils. Sap is milky. Also called Poison Milkweed because it’s toxic to livestock.

FLOWERS: May–September. Flat-topped clusters (umbels) of creamy-white to greenish flowers in the upper leaf nodes; 5 tiny petal-like lobes bend back along the stem, 5 tiny hoods are about as tall as the central column, horns that arch over the column (see photo).

LEAVES: Whorls of 3–4 leaves per node, blades 3/4–4 3/4-inches (2–12 cm) long, to 3/16-inch (1–4 mm) wide. Note the shoots of dwarf leaves in some of the axils.

HABITAT: Sandy-loam, gravelly soils, roadsides, riparian areas; grasslands, pinyon-juniper-oak woodlands.

ELEVATION: 3,100–7,800 feet.

RANGE: AZ, CO, ID, KS, NV, NM, OK, TX, UT, WY.

SIMILAR SPECIES: 32 species of milkweed in NM. Whorled Milkweed, A. verticillata, has whorls of 4–8 leaves and no leaf shoots in the axils.

NM COUNTIES: Statewide in in low- to mid-elevation, dry habitats.