July 7th – July 14th, 2012. Rosepinks
(Sabatia angularis) are one of my favorite wildflowers. With the drought, I’d
almost given up hope of seeing them in bloom this year. But then we saw them in
the Wilson Shoals WMA (Banks County, Georgia) and, last weekend, in Hancock
County, Georgia, where we saw them last year.
I wanted to learn more about this
plant since it was obvious that the style was not fully extended when the
flower first opened but became erect over a number of days to expose the stigma
for fertilization. Marvin at Nature in the Ozarks demystified the process.
Sabatia angularis is unusual in
being protandrous, meaning that the anthers release their pollen before the
stigma of the same flower is receptive to fertilization. This minimizes
self-fertiliation and promotes cross-fertilization to maximize genetic
diversity in the species. There is a good description of this process here.
The plants we found were blooming profusely
When
the flowers open the style, which is bifurcated but twisted closed to prevent
access of pollen to the stigma, lies back against the petals with the branches
of the stigma folded until the flowers supply of pollen is depleted.
The
style then stiffens, lifting it off the petals.
*****
*****
*****
The
bifurcated section begins to unwind, until the...
style
with stigma stand erect above the petals. The stigma is then accessible to
pollen from other flowers.
Sabatia angularis is
known by the common names Rosepink Rose-pink, Bitter-bloom, Common Marsh-pink,
and Square-stem Rose Gentian. Plants are biennials. They are native to the
United States where they occur in the Eastern United States (excepting the New
England states) to Florida and west to Kansas, Oklahoma, Texas and New Mexico.
In Georgia, they occur mainly in counties in the Piedmont. We saw these first
in Gilmer and Pickens counties in North Georgia in July, 2010; last year, we
saw them in Taliaferro, Hancock, and Jasper counties.
Click
on an image to view a larger image
Identification
resources:
- Southeastern
Flora: Rosepink (Sabatia angularis)
- Natural
and Naturalized Plants of the Carolinas and Georgia: Sabatia angularis (Rose-pink, Bitter-bloom, Common Marsh-pink)
- Duke
University, Jeffrey Pippen: Sabatia angularis (Rose Pink, Common Marsh Pink,Bitterbloom)
- Missouri
Plants: Sabatia angularis
- Kansas Wildflowers and Grasses: Sabatia angularis
Distribution:
- United
States Department of Agriculture Plants Database: Sabatia angularis (Rosepink)
- University of North Carolina Herbarium: Sabatia angularis
Related
post:
2 comments:
Wonderful photos and description! Found these today on the Bartram Trail, and enjoyed seeing your wonderful photos of how the style unfolds.
Glad you enjoyed them. It's fascinating how many different mechanisms plants develop to encourage or discourage diversity.
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