Asclepiadaceae: Milkweed subfamily
This family has recently been combined with the Apocynaceae family and is now considered a subfamily. While the old classification designated about 2000 species in 250 genera, the new classification lists 348 genera, with about 2900 species.
We have left this page in the list because of the unique nature of the pollination system. The anthers produce pollen that area grouped into pollinia which are transferred as packets for pollination. This system is extremely advanced in and somewhat resembles the method employed by orchids.
Some of the most unique and recognizable ascelpiods are the milkweeds. These plants are used by monarch butterfly caterpillars as food plants. They take the toxic alkaloids found in the milky sap of these milkweeds and convert it into compounds within their own bodies which make them unpalatable.
Asclepiods have simple leaves that are almost always opposite or whorled. In several species they are succulent. Flowers have both male and female parts (bisexual) and are actinomorphic (which means they can be divided into symmetrical halves on more than one plane, much like a star can be divided into several equal identical pieces). There are 5 petals and 5 sepals. Stamen are highly modified into paired sacs called pollinia. One massive, 5-lobed stigma is usually found in the middle. Fruits (which are follicles) produce seeds which have a tuft of hair on one end.
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