Hydrilla grows so rapidly that it crowds or shades more desirable aquatic plants. Hydrilla is easily confused with Elodea spp. Both Elodea spp. It is somtimes listed as L. muscoides var. Leaves are 0.6 to 0.8 inches long and lance-shaped with edges that are slightly serrated or smooth.
Leaves often curl downward.
Leaf color is usually green with a green midrib. Male and female flowers appear on different plants and are small and have 3 turned-back petals. Lagarosiphon occurs in still-water lakes and ponds or in flowing streams or rivers. It outcompetes native aquatic plants and poses many of the same problems as hydrilla. There are many species of Lagarosiphon but only L. major is prohibited in Texas.