STUDIES IN THE COMPOSIT. 211 
^ MEGALODONTA. 
4 M. Becki. Bidens Beckii, Torr. Fl. N. Y. i. t. 58; Gray, 
Syn. Fl. 298; Britton & Brown, Ill. Fl. 440, fig. 3950. 
Solitary head short-peduncled, the peduncle } inch long 
more or less: bracts of outer involucre obovate to oblong, 
nearly erect, resembling the inner, only of more foliaceous 
texture: rays broad and showy, about 12-nerved, retuse or 
almost obcordate at apex and 3-toothed, the acute middle 
tooth shorter than the obtuse lateral ones. 
Important as characters of the corolla must be, they have 
been almost utterly disregarded here; probably not even 
investigated. In the original plate, in the New York State 
Flora, not the least intimation is given of the real form of 
the rays of this plant. In the figure given by Britton & 
Brown, there is some approach made to the truth, for there 
the ray is shown as retuse; but the draftsman, following 
the vaguest conventionalities as to the indicating of longi- 
tudinal nerves, has brought out three, whereas in the object 
as it exists, either fresh or dry, there are plainly from 
eleven to thirteen, all being of nearly equal prominence. 
M. nupata. Submersed foliage ampler, apparently 
firmer than in the last, less apt to collapse when withdrawn 
from the water: heads smaller, on almost or quite naked 
slender peduncles 2 to 4 inches long, the 1 or 2 emers 
leaves when present alternate and deflexed, dissected or at 
least pectinate-toothed: bracts of outer involucre much 
smaller than the inner, ligulate and spreading; those of 
the inner yellowish: rays oblong-linear, 7 to 9-nerved, nar- 
rowed and obscurely tridentate at apex: styles more slender, 
and more elongated than in the last: fruit not seen. 
Apparently altogether distinct from the type-species by 
