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Have
You Seen This Plant? Giant salvinia, Salvinia molesta, is an aquatic fern prohibited in the United States by Federal law. Status: Currently invading sites in Texas and Louisiana, giant salvinia has the potential to infest aquatic habitats, wetlands and rice fields across the South. Native to South America, its introduction by humans has caused severe economic and ecological problems in many countries including New Zealand, Australia and South Africa.
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| The Problem: Giant salvinia grows rapidly to cover the surface of lakes and streams, spreading aggressively by vegetative fragments. It forms floating mats that shade and crowd out important native plants. Thick mats reduce oxygen content and degrade water quality for fish and other aquatic organisms. Mats impede boating, fishing, and swimming and clog water intakes for irrigation and electrical generation. |  |
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Characteristics: Oblong floating leaves, 1/2 to 1 1/2 inches long. Young plants have smaller leaves that lie flat on the water surface. As plants mature and aggregate into mats, leaves are folded and compressed into upright chains. Leaf surfaces have rows of cylindrical hairs topped with four branches that are joined at the tips to form a "cage" (view with hand lens). These hairs give a velvety appearance and repel water. Distinguish from common salvinia, Salvinia minima, which has leaf hairs with branches always free at the tips. Underwater root-like structures conceal stalks with egg-shaped spore cases attached. Spore cases are not found on young plants. |
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| Prevention: Plants can be carried overland on anything entering infested waters. Boaters and anglers can help prevent spread by removing all aquatic plants from propellers, intakes, trailers and gear before leaving a launch area. Always blow out jet ski intakes and wash boats and equipment land-side before traveling to a new waterway. | |||