Podostemum ceratophyllum Michx.

Horn Leaf Riverweed; Threadfoot

Herb

Perennial

Vascular

Horn Leaf Riverweed is a native perennial in the Riverweed family (Podostemaceae). Horn Leaf Riverweed is a submerged aquatic plant growing attached to rocks in riffles, waterfalls, and other areas of shallow, swift flowing water. It can be found throughout Alabama where suitable habitat occurs. Horn Leaf Riverweed grows tightly attached to rocks by the means of haptera (fleshy disc-like outgrowths) that are produced along its roots. Leaves are olive green in color and repeatedly forked and divided into linear segments. They are attached alternately along the stem. Flowers are produced when plants are exposed by low water levels. The flowers occur in groups of 1-12. The tepals (sepals and petals) are small and scale-like, making them very inconspicuous. Each flower consists of one ovary and two stamens. The fruit is a capsule. Horn Leaf Riverweed is an unusual flowering vascular plant that more closely resembles an algae or moss. It often forms extensive mats in suitable habitat. It has been associated with extremely high secondary production of benthic macroinvertebrates, and is an important component in stream productivity. Horn Leaf Riverweed also provides shelter for many species.--A. Diamond

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Native

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