It is proposed to include Family Asclepiadaceae within Family Apocynaceae. I will not make this change at this time, January 2010.
The milkweeds are known for their milky juice and their odd flower structure. The petals of the 5-parted flowers are reflexed and the anthers unite to the stigma in the form of a crown with 5 hood-like appendages. Each flower can form 2 follicles from its 2 ovaries. The numerous seeds bear tufts of silky hairs at their tips for efficient wind dispersal. (Dale 48).
This is a very large family of plants containing about 2,000 species. They include perennial herbs, vines, or shrubs with milky juice. The principal genus in California is Asclepias, of which there are some 11 species. (Robbins et al. 335).