SPECIES AT A GLANCE and Brazilian

closer, Brazilian elodea have smooth edges and no spines on the midrib of the and whorls of four to six leaves, whereas hydrilla has serrations on the leaf edge and spines on the midrib of the leaf and whorls of five leaves. Native elodea has whorls with three leaves. Hydrill­ la produce small tight axillary reproductive buds called “turions” at stem nodes and potato-like “tubers” with its underground stems. Both turions and tubers enable Hydrilla to overwinter and persist through harsh environ­ ments. Both of these were initially sold for use in aquari­ elodea.co.uk elodea.co.uk ums and aquatic gardening, but they became established Hydrilla (Hydrilla verticillata) and Brazilian elodea in water bodies through their intentional release. Both ( densa) are invasive aquatic plants that occupy plants can quickly infest underwater , with freshwater habitats. While hydrilla is native to , , twisting, submersed vegetation that can produce a and eastern , and Brazilian elodea is native to dense, impenetrable canopy at the water’s surface. This , both plants are invasive to North America. interferes with native growth and impedes recre-

Because these plants are related and both have pointed ational activities such as boating or swimming. Hydrilla green leaves that whorl up the length of the stem, they and Brazilian elodea outcompete native species by may be difficult to distinguish at first glance. Looking growing rapidly in lakes, ponds, marshes, and streams.

Species in the news Learning extension Resources NY lawmakers uprooting aquatic Measure how fast Brazilian elodea can State of Washington Department of : http://www.ithacajour­ grow in classroom experiments Ecology: www.ecy.wa.gov/programs/wq/ nal.com/story/news/2014/06/23/ plants/weeds/

Why you should care water bodies where they rapidly grow and become Invasive aquatic plants compete with native plants invasive. Hydrilla reproduces through fragments for resources. They form thick tangles of vegetation containing a leaf node or whorl and by underground that cover public and private waterways, shade out tubers. Brazilian elodea can reproduce through the native plants, and eliminate for and other spread of plant fragments, with specialized “double wildlife, sullying recreational areas as a result. People nodes” on the stem that can become a new plant. and animals can get disoriented and entangled in dense mats of hydrilla and Brazilian elodea. These What you can do submersed plants can spread to new areas from small Never release nonnative plants of any kind into plant fragments, making it particularly easy to expand a waterbody. Clean boats and trailers of all aquatic their range. Both species are difficult to eradicate plants and mud when exiting a waterway. Learn how once established, since leaving only a small fragment to recognize native elodea and be able to distinguish it of them can result in continued plant growth and from Brazilian elodea and hydrilla. In Oregon, report reinfestation. invasive plants by calling 1-866-INVADER or visiting How it got here and spread www.oregoninvasiveshotline.org/ Hydrilla is native to the old world (Asia, Af- COOL FACT rica, parts of ) and Brazilian elodea is native Hydrilla stands can become so thick that ducks and other to South America. They were typically introduced birds can walk on top of them at the water’s surface. through the trade and shipment. If the plants are improperly discarded, they can end up in

Oregon Sea Grant Aquatic Invasions! A Menace to the West • SPECIES GUIDE 1