190 PROCEEDINGS OF THE AMERICAN ACADEMY 



This tip, moreover, while sometimes conspicuously prominent, is obso- 

 lete or barely perceptible in one or more species of every group the 

 genus comprises. We have in North America only 8 species of Oxy- 

 tropis, all northern or montane ; and Europe has about as many ; but 

 the Flora of the Russian Empii'e boasts of sixty-one species. Ought 

 Oxytropis to be retained as a genus ? On the one hand there is a gen- 

 eral congruity of the species in habit ; on the other, 0. Lapponica, 

 with the technical generic character almost obliterated, and others of 

 that group, very closely resemble species of Astragalus with which they 

 are geographically associated. Moreover, the technical generic char- 

 acter is of no such value in Indigofera. 



Probably the best support of the genus, notwithstanding the reduc- 

 tion of Pliaca to Astragalus, has been the constant coincidence of 

 the pointed keel of the corolla with the introflexion of the ventral 

 suture ; in other words, that no Astragali, in the strict sense, are known 

 with a pointed keel. There are, however, among American species 

 some Astragali and Phacce with the keel either considerably attenuated 

 upwards or acutish. And at length we have one from Arizona, 

 described at the end of the genus, under the name of A. nothoxys, 

 which, along with the habit and the dorsally bilocellate legume of 

 a true Astragalus, has in the corolla a sharply acuminate keel ! Still, 

 although Oxytropis could hardly be more completely invalidated than 

 by this discovery, I think it probable that it may still be kept up, on 

 the ground of general convenience. 



If Phaca must needs be merged in Astragalus, it is obviously de- 

 sirable that the change should be made as soon as possible, and the 

 requisite alterations in nomenclature effected. Moreover, our species 

 greatly needed revision, and reduction to some systematic arrange- 

 ment. In this view, having obtained from their obliging proprietors 

 the important materials in the herbaria of Dr. Torrey, Mr. Du- 

 rand, and of the Philadelphia Academy (containing the types of 

 most of Nuttall's species), and collated them with those of my own 

 herbarium, I have devoted much time to the study of these plants ; and 

 the result is herewith presented. 



The general order is from the completely bilocellate legumes, 

 through the imperfectly bilocellate, to the strictly unilocular species ; 

 with no attempt (which would be hopeless) to dispose the groups in 

 any natural series. When brought into proper form for a systematic 

 work, the gi'oups themselves would be considerably condensed, reduced, 

 or subordinated. 



