Owing to the abundance of, material found during the past vacation at Bankson Lake, Cass Co., Mich., as also because of the unique character of the plant itself as a submerged composite, it was considered possible that the anatomical study of Megaladonta BeAkii (Torrey) Greene would show some interesting features structurally. following notes are the result of the investigation of the plant, Which is rather abundant in the places where it is found, but has not been reported from many localities in our region. plant was first discovered by Dr. Lewis C. Beck in Schuyler's Lake near Schenectady, N. Y. It was published by Torrey who referred it to the genus Bidens as Bidens Beckii in i82I.' Dr. E. L. Greene2 raised the plant to generic standing as type of his new genus Megalodonta. He published at the same time a second species M. nudata from the Adirondacks, and another species from Greene Lake, Washington. As characteristic distinctions from the genus Bidens is mentioned especially the. singular peculiarity not only among the Bidentideae as a group but even of the whole composite family, aquatic habit withsubmersed and dissected foliage not so much different in appearance from that of Batrachium (Ranunculus) aquatile (Linn.) Wimm3. of the old world or our own Batrachium trichaphyllum Chaix) Bosch.4 flowers both ray and disk are peculiar. rays are retuse and notched instead of obtuse and entire. The disk corollas are slender and clavate. The achenes with their not at all compressed or angled but almost terete body surmounted by several 'long stout persistent awns of great size and prominence in relation to the essential part the fruit5 are the other characters of note. generic name of the plant is derived from the Greek Torrey, J. in Spreng. Neue Entdeck., 2, p. 135 (I82I) also Torrey, J., Flora of New York, I, p. 388, pl. 68, (I843), Torrey, J., Compend. p. 312 (I826)) Spreng. Syst. 3, p. 455, (1826), Beck, L. C., Botany, p. 207 (I833)