About Asclepias linaria Cav.
Asclepias linaria Cav. is a species of milkweed, commonly called pineneedle milkweed. It is native to the Mojave and Sonoran Deserts of northwestern Mexico and Arizona. This plant is a large, erect perennial herb or shrub, covered in hairs, and bears many narrow green leaves that resemble pine needles. Its flowers grow in umbel-like clusters; each individual flower has pink-tinted rounded hoods at its center and greenish reflexed corollas. It produces a fruit that takes the form of a follicle. Asclepias linaria acts as a larval host plant for the monarch butterfly. Research has found that this species has a very high cardenolide content, which reduces the impact of the OE parasite, Ophryocystis elektroscirrha, on the monarch butterfly, Danaus plexippus. In comparison, some other Asclepias species have very low levels of cardenolides.
