Najas guadalupensis

Najas guadalupensis is a species of aquatic plant known by the common names southern waternymph, guppy grass, najas grass, and common water nymph. It is native to the Americas, where it is widespread. It is considered native to Canada from Alberta to Quebec, and most of the contiguous United States, Mexico, Central America, the West Indies and South America. It has been introduced in Japan, Israel and Palestine.