238 
p. 30.) is equally applicable to the one species as to the other, 
correctly to neither: “C. rotundifolia, caulibus simpliciusculis 
debiliter procumbentibus, foliis omnibus simpliciculis sub- 
orbiculatis integriusculis.” Some years ago, Dr. Boott’s 
specimens of C. rhomboidea, Dec., were compared with 
Michaux's Herbarium, and pronounced by Richard himself 
to be the C. rotundifolia, Mich.,—as certified upon the 
paper containing the specimens. It was from these facts 
that I was led to consider the two species identical in my 
Flora; and I should have continued in error were it not 
for Dr. Darlington's criticisms, and for beautiful specimens 
of the two plants which I received from Dr. Darlington, 
along with many other rarities, through the kindness of my 
inestimable friend Dr. Boott. Persoon has made no altera- 
tion in the specific character of Michaux's C. rotundifolia ; 
but under the genus Arabis he has given the C. rhomboidea 
of De Candolle; according to tbis latter author under two 
names: * 4. rhomboidea, foliis glabris rhomboideis, infimis 
longe petiolatis, radice tuberosa ;" and * 4. tuberosa, caule sim- 
plice, foliis lato-lanceolatis dentatis inferioribus subpetiolatis. 
radice tuberoso-fibrosa." The former of these two specific 
names (though, in my opinion, by far the least appropriates) 
has been adopted by De Candolle for this the tuberous-r 
kind, which he has rightly referred to Cardamine ; and this 
species is followed, first, in the Systema Vegetabilium, and, 2dly, 
in the Prodromus, by the C. rotundifolia, with the amended 
character, * foliis orbiculatis subdentatis glabris petiolatis, 
caulibus debilibus procumbentibns, radice fibrosa." Nuttall 
has quoted the C. rotundifolia of Mich., but doubtfully, as 4 
synomyn to A. rhomboidea. Pursh has a C. rotundifolia of 
Mich., and an Arabis rhomboidea of Persoon, copying the 
characters of the respective authors verbatim, and offering 
no remarks. Dr. Bigelow has adopted the Arabis rhomboidea 
of Persoon, and given a good description. That author's *C- 
rotundifolia, Mich." is given, with a mark of doubt, as the true 
plant of Michaux, and is in reality a very different species (C 
bellidofolia), inhabiting thehighest summit of the White Moun- 
tains. The latest work on American Botany that I have the oppor 
