About Asclepias oenotheroides Cham. & Schltdl.
Zizotes milkweed, scientifically named Asclepias oenotheroides Cham. & Schltdl., is a small perennial herb that grows from an underground modified rhizome stem. It typically produces one to seven usually unbranched stems, which may occasionally branch near the plant's base. Each stem grows 10 to 50 centimeters (4–20 inches) long, spreading outward from the plant's crown or lying along the ground, and is covered from sparsely to densely with curved hairs. Its leaves grow oppositely, or nearly oppositely, along the stems, with outlines that are egg-shaped, somewhat rectangular with rounded corners, or a rounded triangle. The leaves measure 4–11 cm (1.5–4.5 in) long and 1.2–6.5 cm (0.5–2.5 in) wide, and sometimes have slightly wavy margins. Its flower clusters, called inflorescences, are umbels: all individual flower stalks connect at a single point, forming a shape like umbrella ribs. Lower umbels grow from the stem on a stalk called a peduncle, while upper umbels attach directly, or nearly directly, to the stem. Each flower has five petals that are fused at the base, with greenish-white lobes. Flowering can begin as early as February, though it most often starts in March, and can continue as late as November. This milkweed is native to North and Central America, ranging from Colorado and Louisiana in the United States south to Costa Rica. In Central America, it grows in every country except Belize and Panama. It is widespread across Mexico, found in 24 of the country's 36 states. Within the United States, it occurs in Arizona, New Mexico, Colorado, Oklahoma, Texas, and Louisiana. It is widespread in Texas, particularly in the southern half of the state. In New Mexico, it is much less common, and has only been recorded in Chaves, Santa Fe, and San Miguel counties. Similarly, it has only been recorded in Blaine and Major counties in Oklahoma. In Arizona, Colorado, and Louisiana, it has only been recorded in a single county in each state: Cochise County, Arizona; Las Animas County, Colorado; and Jefferson County, Louisiana. In the southern United States, zizotes milkweed is an important host plant for monarch butterflies, alongside Asclepias viridis and Asclepias asperula.
