270 PITTONIA. 
Nor, indeed, has any botanist a right to apply any old 
name where he can not determine from the description 
what the original plant was. 
7. Generic Rank for Broens Becxu, Torr. 
In some particulars nearest of kin to B. chrysanthemoides 
and its immediate allies stands what has hitherto been 
known as Bidens Beckii. It is singular, among not only 
Bidentidee but our American Composite as a whole, in 
being actually aquatic, as much so as Ranunculus aquatilis. 
The greater proportion of its foliage is submersed and capil- 
laceously multifid, suggesting no other bidentideous foliage 
whatsoever, unless we should look upon that of Coreopsis 
verticillata as being analogous, which it scarcely is. But the 
few pairs of emersed leaves in this plant recall the foliage 
of B. chrysanthemoides and its near relatives; and the 
involucre is more like that of these than of other groups of 
Bidens species. But the flowers, whether of ray or of disk, 
have other characters. The rays here are both retuse and 
notched, instead of being obtuse and entire. In those speci- 
mens examined by me in which the rays are best preserved, 
I find the tip of the ray obcordate but with a distinct short 
cusp between the two lateral rounded lobes. It is a mode 
of apical tridentation not otherwise observed by me in this 
subfamily of composites. The disk-corollas are slender 
and clavate, as in the group to which B. frondosa belongs. 
The achenes, with their not at all compressed or angled 
but almost terete body, surmounted by the several long 
stout persistent awns of very great size and prominence, in 
relation to the essential part of the fruit, are what I consider 
to be those of an very good genus; and I name it 
