Excerpts from Jim Conrad's
from the May 6, 2012 Newsletter issued from the woods of
the Loess Hill
Region a few miles east of Natchez, Mississippi, USA
SWAMP DOGWOOD FLOWERING
Our landscape couldn't be greener nowadays. The greenness is less the soft, luminescent, yellowish hue of spring than the harder, more serious and subdued green of early summer. Looking at the forest, you can almost hear the ecosystem's powerful, efficient and mystical photosynthesis. It's easy to imagine that within such a vast seriousness of shadowy greenness it may be hard for a little flower to draw attention to itself.
In this context the pollination strategy of many plant species is to produce flowers as bright as possible -- white ones -- and to cluster them to make a larger visual impact. Biking down backroads, again and again, dense panicles of white flowers nod from the forest's edges. You can see what the leaves and flowers of one such 10-ft-high (3m) species look like above.
Notice how the leaves arise two to a stem node -- they're "opposite" -- and that the flowers are clustered in flat-headed panicles held aloft by slender peduncles at branch tips. A flower close-up is shown below:
There you see that each flower has four widely spreading petals, four stamens and a single thick style arising from the center of a doughnut-like disk. The stamens' filaments and the petals arise from beneath the disk. The flowers are "inferior," meaning that the petals and stamens arise above the ovary -- the future fruit -- not below it.
All these features point to the fact that here we have a dogwood flower, though it's very different from what most people think of as dogwood flowers. Most people visualize the white items that adorn Flowering Dogwoods in spring, but those are actually flowering heads, or inflorescences, as we've seen on our Flowering Dogwood page at http://www.backyardnature.net/n/w/dogwood.htm.
Lower down on that page you can see the yellow corollas of the Flowering Dogwood's "real" flowers, and those flowers with their four petals, four stamens and thick style do look like the white dogwood flowers we're considering now.
What we have here is the Swamp Dogwood, also called Silky Dogwood, CORNUS AMOMUM, fairly common in bottomland soils throughout the eastern US and southernmost Canada.
Most folks are surprised that dogwoods exist other than Flowering Dogwoods. However, just in Mississippi seven dogwood species are listed, and only one, the Flowering Dogwood, bears large, white, petal-like bracts making the flower head look like a single flower.
In the fall Swamp Dogwood produces pretty blue drupes that birds eat. Native Americans traditionally used Swamp Dogwood medicinally -- a decoction of the roots for relieving urinating pain and as a laxative, an infusion of the bark to wash babies and make them sleep, for chest congestion and for gonorrhea sores, and there were other uses as well.