Asclepias
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| Missing image Asclepias1810.JPG Asclepias Asclepias in bloom, showing pollinators | ||||||||||||||
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Asclepias L. (1753), the milkweeds, is a genus of herbaceous perennial, dicotyledonous plants that contains over 140 known species. It used to belong to the family Asclepiadaceae, but is now classified in the subfamily Asclepiadoideae of the dogbane family Apocynaceae.
Milkweeds are an important nectar source for bees and other nectar seeking insects, and a larval food source for monarch butterflies. Milkweed is named for its milky juice, which contains alkaloids, caoutchouc, and several other complex compounds including cardenolids. Some species are known to be toxic.
Carolus Linnaeus named the genus after Asclepius, the Greek god of healing, because of the many folk-medicinal uses for the milkweed plants.
Species in the Asclepias genus grow their seeds in pods. These seed pods contain soft filaments known as either silk or floss. The filaments are attached to individual seeds. When the seed pod ripens, the seeds are blown by the wind, each carried by several filaments.
Species
Some Asclepias species:
- A. acida
- A. amplexicaulis - Blunt-leaved milkweed
- A. curasavica - Scarlet milkweed, Bloodroot, Bastard Ipecacuanha
- A. exaltata - Poke milkweed
- A. incarnata - Swamp milkweed
- A. lanceolata - Lanceolate milkweed
- A. linearis
- A. obovata
- A. purpurasens - Purple milkweed
- A. quadrifolia - Four-leaved milkweed
- A. rubra - Red milkweed
- A. speciosa - Showy milkweed
- A. sullivantii - Sullivant's milkweed
- A. syriaca - Common milkweed
- A. tuberosa - Butterfly weed, Pleurisy root
- A. variegata - White milkweed
- A. verticillata Whorled milkweed
- A. vincetoxicum
Missing image
Milkweed4043.JPG
Image:Milkweed4043.JPG
Baldwinsville, New York
Uses
These milkweed filaments or floss are coated with wax, and have good insulation qualities. Tests have shown them to be superior to down feathers for insulation. During World War II, over 11 million pounds of milkweed floss were collected in the United States as a substitute for kapok.
In the past, the high dextrose content of the nectar led to milkweed's use as a source of sweetener for Native Americans and voyageurs.
Milkweed latex contains about 1-2% caoutchouc, and was attempted as a natural source for rubber by both Germany and the United States during World War II. No record has been found of large-scale success.
External links
- Medical research (http://www.terapeta.net/asclepias.pdf)
- Milkweed test-cultivated for the insulation value of floss (http://www.hort.purdue.edu/newcrop/proceedings1993/v2-428.html)
- Milkweed tested at Purdue for paper-making and animal feed (http://www.hort.purdue.edu/newcrop/duke_energy/Asclepias_syriaca.html)
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