Monday, June 27, 2011

Redring or White Milkweed (Asclepias variegata)

Asclepias variegata is known by the common names Redring or White 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 terminal umbels. In contrast to the Clasping Milkweed (Asclepias amplexicaulis) which have a single umbel, some Asclepias variegata plants have two or three terminal umbels. Flowers are white with a red ring between the sepals and the upper part of the flower. So far, we’ve found single plants Asclepias variegata in Wilkes and Hancock counties and several plants in Fort Yargo State Park in Barrow County. Plants bloom in May - June in this area.

Plants at the edge of the woods in Fort Yargo State Park in Barrow County, Georgia.

A closer view. The leaves are broad but have a pointed tip unlike the leaves of the Clasping Milkweed which have blunt ends

Several views of the multiple umbels that are common on Redring Milkweed plants. The flowers are in tight clusters

This photo shows the red ring that gives this species one of its common names.

A closer view of an individual umbel. You can just spy some legs of a crab spider at the top of the umbel in this photo.

I saw several crab spiders, including this male spider, on the plants in Fort Yargo State Park.

Close view of the flowers. The hoods of Amplexicaulis variegata are shaped quite differently from those of Asclepias amplexicaulis. The hooks of A. variegata are closed tightly over the stigmatic disk comparison with those of A. amplexicaulis that are ‘loose.’

The hoods of the Asclepias variegata almost touch, compared with those of Axclepias amplexicaulis.

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 of
Axclepias amplexicaulis here.
Asclepias variegata (
Redring or White Milkweed) is native to the United States. It is found in states east of a line from Illinois, Missouri, Oklahoma and Texas; it’s not found in the New England states. It is found in Ontario, Canada. In Georgia, plants may be found more frequently in the Piedmont counties than in coastal plain counties.

Click on an image to view a larger image


- United States Department of Agriculture Plants Database: Asclepias variegata (Redring Milkweed)

Identification resources:

- Southeastern Flora: White Milkweed (Asclepias variegata)

- Missouri Plants: Asclepias variegata

- Natural and Naturalized Plants of the Carolinas and Georgia: Asclepias variegata (White 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): Flowers

- Green Comet Milkweed (Asclepias viridiflora)

No comments: