hippuris vulgaris, mare's-tail perennial herb, aquatic plant with leaves occur in whorls, poland, europe

biodiversity eurasia europe hippuris vulgaris plantaginaceae biology blooming botany ditches ecology flower green habitat herb iceland journey mare stail methane mudflats nature nonacidic north perennial plant plants symetry vegetation water waters mare's-tail common aquatic america prefers non-acidic leaves occur whorls poland inconspicuous flowers