Clasping Milkweed (Asclepias amplexicaulis): Flowers

From: Clasping Milkweed (Asclepias amplexicaulis): Shoots, Leaves And Flower Buds

Asclepias amplexicaulis is known by the common names Clasping Milkweed, Blunt-leaved Milkweed, Blunt-leaf Milkweed, or Sand milkweed. Asclepias sp. are perennial and are among the last perennials to emerge in the Spring. Plants may grow from seed or from rhizomes in a single stalk as high as 3-4 feet tall. Flowers form in a terminal umbel. Flowers may be pink, purple, or maroon or even a brownish pink.

An individual flowering plant (Ogeechee WMA, Hancock County, Georgia)

Greene County, Georgia

Broad River WMA, Wilkes County, Georgia

A cluster of blooming plants

Greene County, Georgia

Broad River WMA, Wilkes Co, Georgia.

Ogeechee WMA, Hancock County, Georgia

Flower umbels. The flowers in the umbel are loose, not in a tight cluster like the Green Comet Milkweed (Asclepias viridiflora)

Flower just starting to open.

The corrolas open to form a star but soon…

Fold back further…

Until they lie against the flower pedicel.

Close view of the flower, front on

Close view of the flower; slight angle

Asclepias flowers appear ‘clean’ because they don’t have loose pollen grains that dust the flowers. Asclepias flowers are unusual; diagrams of the anatomy of the flowers may be found here. The pollen is contained in sacs called pollinia that are located between the anthers. Two pollinia are connected by a ‘thread’ called a translator to a body called a corpusculum. Pollination only occurs if an insect is strong enough to hook the corpusculum and pull the pollinia from their sacs and deposit them on the stigmatic disk of another flower. You can see a photograph of the pollinia here.

A view showing the corpusculum - the black spot in the middle of the image - that connects the pollinia that are located in the adjacent anther sacs hidden by the flower hoods.

Next – and it may take a while – the 64-million-dollar question is whether flowers have been fertilized and will seed pods develop and release seed. Stay tuned.
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Distribution:
- United States Department of Agriculture Plants Database: Asclepias amplexicaulis (Clasping milkweed)
- University of North Carolina Herbarium: Asclepias amplexicaulis

Identification resources:
- Southeastern Flora: Clasping milkweed (Asclepias amplexicaulis)
- Missouri Plants: Asclepias amplexicaulis
- Kansas Wildflowers and Grasses: Blunt-leaf Milkweed
- Natural and Naturalized Plants of the Carolinas and Georgia: Asclepias amplexicaulis (Blunt-leaved Milkweed, Clasping Milkweed)
- Wayne’s World: Botany 110. Flower Terminology Part 1, 4. The Remarkable Bisexual Milkweed Blossom

Related posts:
- 2010: Year Of The Wildflower – Wildflower Index
- Clasping Milkweed (Asclepias amplexicaulis): Shoots, Leaves And Flower Buds