Brasenia schreberi J.F. Gmel.

Water Shield; Purple Wen Dock

Herb

Perennial

Vascular

Water Shield is a native perennial in the Water Shield family (Cabombaceae). Water Shield is a floating leafed perennial that grows in shallow ponds and lakes, sloughs, and beaver ponds. Water Shield is common in the southern two-thirds of Alabama, and scattered in the northern third. It is an aquatic perennial with creeping, thin rhizomes rooted in the mud at the bottom of the pond and floating leaves. The leaves are long petiolate, elliptic in outline, with entire margins. The leaves are green above and red below. The vegetative parts of the plant are heavily coated in a clear mucilage. This mucilage is thought to deter herbivores. Flowers extend above the water surface while open. The flowers are singular on long pedicles. The flowers have three thick, greenish-red sepals and three red petals. Flowers are open for a two-day period. On the first day the flower is open it is functionally female, with the stigmas receptive to pollen. At the end of the first day the flower is drawn below the water’s surface. On the second day the flower again extends above the water’s surface and the anthers release their pollen. The flower is then pulled below the water’s surface again and the fruit develop. Water Shield is wind pollinated. There are 4-18 pistils per flower, each with 1-2 ovules. Each fertilized pistil develops into a 1-2 seeded hard, ellipsoid or fusiform fruit. The style persists on the fruit. The fruit is indehiscent (does not split open to release the seed). Water Shield occurs on every continent except Antarctica and Europe. Is Asia, it is grown as a vegetable. The mucilage covering the plant has anti-bacterial and anti-algal properties. Water Shield is often considered a pest as its dense growth interferes with fishing, swimming, and boating. Its leaves help shade the water and lower its temperature and well as providing habitat and cover for fish and invertebrates. The fruit are eaten by water fowl.--A. Diamond

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Native OBL (NWPL) G5 (Global Rank)

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