STUDIES IN THE CRUCIFERS. 121 
able nümber of very clear and excellent species. Of truly 
typical Dentaria there is scarcely one; for even D. tenella of 
Pursh, which is the best of them, has pinnated instead of 
palmated cauline leaves, and a tuberiferous root in place - 
of a rhizoma ; so that even this is rather nearer the ambigu- 
ous group, of which the Cardamine paucisecta of Bentham is 
a type, than it is to any European or Atlantic American 
Dentaria. 
A quite preponderating number of the far-western species 
are so exactly intermediate between true Cardamine and 
Dentaria that it seems difficult to decide to which of the two 
to refer them. As far as vegetative characters go, they are 
perhaps more naturally allied to, or at least more gradually 
confluent with, Cardamine; nevertheless, at the D. tenella 
end of the series they are almost as confluent with true Den- 
taria. But this ambiguous group, while mainly Pacific 
American, is not without Atlantic coast representatives; for 
C. rotundifolia, C. rhomboidea (or bulbosa) and C. Douglassii 
(Britton) belong here. There is not the remotest hint of any 
generic difference between these plants and the Californian 
Dentaria Californica and cardiophylla. If these last-named 
plants and their near kindred are, as placed in the Synop- 
tical Flora, Dentarias, such most indubitably are also the 
aforenamed Atlantic species, though in the book just named 
they are, without the least reason or consistency, retained in 
Cardamine. Nevertheless it is evident that Mr. Watson sup- 
posed his Dentaria species all to be distinguishable from 
Cardamine by a character of the corolla, for he attributes to 
Dentaria what he denies to Cardamine,“ Petals * * * wi h 
slender claws and ovate spreading blades.” This, asa point 
of generic distinction, is quite wrong. The Dentarias proper 
are decidedly more given to exhibiting ascending (not spread- 
ing) petals with blade and claw spatulately confluent than are 
are true Cardamines. Moreover, he has in the same treatise 
merged in one, under Dentaria, two species, one of which 
CS ee 
1 Wats. in Gray, Syn. Fl., i. 104. 
