336 AMERICAN MIDLAND NATURALIST 



THE ANATOMY OF MEGALODONTA BECKII. 



BY A. V. HOECK. 



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 

 Beckii (Torrey) Greene would show some interesting features 

 structurally. The 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. 



The 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 

 1821.' Dr. E. L. Greene^ 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 dis- 

 tinctions from the genus Bidens is mentioned especially the 

 singular peculiarity not only among the Bidentidcae as a group 

 but even of the whole composite family, aquatic habit with- 

 submersed and dissected foliage not so much different in appear- 

 ance from that of Batrachium (Ranunculus) aquatile (Linn.) 

 Wimm^. of the old world or our own Batrachium trichophyllum 

 Chaix) Bosch. "f The flowers both ray and disk are peculiar. The 

 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 fruit "^ are the other characters 

 of note. The generic name of the plant is derived from the Greek 

 ' Torrey, J. in Spreng. Neue Entdeck., 2, p. 135 (182 1) also Torrey, J., 

 Flora of New York, i, p. 388, pi. 68, (1843), Torrey, J., Compend. p. 312 

 (1826)) Spreng. Syst. 3, p. 455, (1826), Beck, L. C, Botany, p. 207 (1833) 

 p. 191 (1848). 



* Greene, E. L., Pittonia, 4, p. 271 (1901). 



» Wimm. Fl. Schles. p. 8(1841). 



^ Bossch, Prod. Fl. Bat., p. 5 (1850). 



5 Greene, 1. c. 



