Hydrilla produces hybernacula, turions in leaf axils and tubers (subterranean turions)
terminally on rhizomes. Turions are very compact dormant buds that are produced in leaf axils
and fall from the plant when they mature. These structures are 5-8 mm long, dark green, and
appear to be spiny. Tubers are formed terminally on rhizomes or stolons and can be found 30
cm deep in the sediment. They are 5-10 mm long and are off-white to yellow unless they take on darker colors from organic sediments.