Potamogeton nomotoensis, a new species from the Nomoto River, Tochigi Prefecture, Japan

Abstract

One new species of Potamogeton, P. nomotoensis, is described from the Nomoto River, Tochigi Prefecture of central Japan. The new species is distinguished from other related species in possessing both submersed and floating leaves and in that a "stipular sheath"is formed by adnation of stipules to the basal part of lamina in the submersed leaves. Potamogeton nomotoensis is probably of hybrid origin, although its parent species are uncertain.