(Hydrilla verticillata)
Not Known To Occur In Colorado
Hydrillais a submersed invasive aquatic plant. It can grow to the surface and form dense mats. It may be found in all types of water bodies. The stems are slender, branched, and up to 25 feet long. Hydrilla’s small leaves are strap-like and pointed. They grow in whorls of four to eight around the stem and below the growing tips are straight or curved. The leaf margins are distinctly saw-toothed. Hydrilla often has one or more sharp teeth along the length of the leaf mid-rib. Hydrilla produces tiny white flowers on long stalks from June to October. Stems typically grow rooted but fragment easily. The plant also produces 1/4 inch turions, or overwintering buds, at the leaf axils and potato-like tubers attached to the roots in the mud. The flowers are wind pollinated.