Asclepias fascicularis

Asclepias fascicularis or Narrow-Leaf Milkweed has leaves that are very slender compared to other, coarser plants in the milkweed family, or Asclepiadaceae. Flowers are a greenish-white with a tinge of purple; fruits are the familiar milkweed pods with their abundant downy seeds inside. Some milkweeds contain poisonous compounds, known as cardiac glycosides, which also accumulate in the tissues of the Monarch caterpillars that feed exclusively on the milkweeds. This means that birds that try to feed on the caterpillars or adult butterflies are poisoned; birds that consume Monarch caterpillars have been photographed vomiting after eating the larvae. Birds quickly learn to avoid eating Monarch larvae or adults and this serves to protect the butterflies.

Plants in the family Asclepiadaceae have been used medicinally for hundreds of years, for treatment of such things as pleurisy, rheumatic fever, and other diseases. Monarch butterflies use this species and others in the genus Asclepias as host plants.

Introduction to Valentien Collection
Gallery of Plants
Monarca: A Gallery of Butterfly Plants

Text by Margaret Dykens