Clasping Venus' Looking-glass

Description:

This native annual plant is unbranched. It is usually ½–1' tall, and rarely becomes taller. The central stem is light green and deeply grooved, with lines of small white hairs along the ridges. The alternate leaves are also light green, and strongly clasp the stem. However, at the top of the stem are a pair of opposite leaves. These leaves are about 1" long and nearly as wide. They are cordate, with wavy or dentate margins that are slightly ciliate. Along the margins the leaves may assume a purplish color in bright sunlight. There is a milky sap in both the stem and leaves. From each leaf axil in the upper half of the plant, are 1-3 flowers, although only one of these will be in bloom at the same time. Each flower is deep violet or purple and about ¾" across. It has a short tubular corolla with 5 spreading lobes. There are darker lines of purple that converge toward the throat of the flower. The throat is whiter than the rest of the flower, from which emerges a prominent white pistil and several stamens. The blooming period occurs during the early summer and lasts about a month. There is no floral fragrance. This plant also produces self-pollinating flowers on the lower half of the stem, whose petals never open. The ovaries develop into small oval capsules, which split open into 3 parts to about the middle. This releases the numerous tiny seeds, which are lens-shaped and reddish brown. They are dispersed readily by the wind, and can be carried a considerable distance. The root system consists of a taproot.

Habitat:

The preference is full sunlight, and mesic to slightly dry soil. This plant flourishes best in poor soil that is either gravelly or sandy. It doesn't tolerate much competition from taller plants. This one was photographed at the Savannah National Wildlife Refuge near Hardeeville, SC.