Contemporary Circumscription Compared with A Utah Flora 4th ed.

Bio430

Apocynaceae including Asclepiadaceae

The milkweeds have been traditionally recognized as a family (Asclepiadaceae) and are treated as such in A Utah Flora.  This group is monophyletic, but derived within the Apocynaceae.  The close relationship between the groups has long been recognized and they share the unique feature of a gynoecium with two unfused ovaries, yet fused stigmas.  The Asclepiads have a corona (associated with stamens and gynoecium) which other plants in Apocynaceae lack; other aponcynacae also have the gynoecium fused from the style to the tips, rather than just at the stigma.

Key Features

Plants with opposite leaves (mostly) and milky latex; flowers are 5-merious with a distinct gynoecium composed of a single pistil formed from 2 carpels; the ovaries are free, but either the style or just the stigmas are fused. Stamens are epipetalous or fused to the gynoecium with extra outgrowths forming a distinctive corona.