Sunday, August 26, 2012

Maryland Or Wild Senna (Senna marilandica)

August 11th, 2012. We’d seen this plant in the Fishing Creek Wildlife Management Area in Wilkes County previously but hadn’t stopped to take a closer look. This time we did. The plant was a little taller than 6 feet. It was in bud but with only one flower actually open. I didn’t manage to get a good shot of the entire plant but it was about 6 feet tall.

 The top of the plant with the single, open flower at the bottom right.

A closer view of the buds at the top of the stem

The compound leaves

A close-up view of the flower and buds.


 Close views of the flower.

Ants were clustered around the base of the leaf and flower stem.

These plants have extra-floral nectaries - glands that may be dome-shaped and dark gray-purple, with or without a short stalk at their base. The gland on this plant was sessile (no stalk) and dark green in color.

Senna marilandica (Maryland or Wild Senna) is native of the United States where it’s found in states east of a line from Illinois to Kansas south to Texas. In Georgia, it’s only been documented in a few counties, including Wilkes County, in north, central and southern Georgia.

Another species, the American or Northern Wild Senna (Senna hebecarpa), has only been documented in Fulton and DeKalb counties in Georgia. The extra-floral nectaries in this species appear to be located further along the leaf stem rather and in the axil between the leaf and stem.
Click on an image to view a larger image

Identification resources:
- J. Pippen, Duke University: Senna marilandica (Maryland or Wild Senna)
- Illinois Wildflowers: Maryland Senna (Senna marilandica)

- United States Department of Agriculture Plants Database: Senna marilandica (Maryland Senna)

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