STUDIES IN THE CRUCIFER.E. 125 
had been referred variously to Brassica, Cheiranthus, Ery- 
simum and Sisymbrium, Sir William following De Candolle 
and Bieberstein in calling it Sisymbrium junceum. What 
relation our American plants sustain to the Old World 5. 
junceum I know not; but they who have compared speci- 
mens seem to have agreed quite unanimously that ours rep- 
resent at least a distinct species, or perhaps two species; so 
that Sisymbrium junceum is now excluded from the Amer- 
ican flora; while to our forms has been assigned the name 
Sisymbrium linifolium, a name which doubtless embraces 
two species, if not three, at present more or less imperfectly 
nown. | 
W yeth's specimens formed the basis of two species as pro- 
posed by Nuttall, namely, Nasturtium pumilum and N. lini- 
folium. Very shortly after Hooker's cataloguing of Sisym- 
brium junceum as an American plant on the authority of 
Douglas' specimens, Nuttall published the aforenamed in 
the Journal of the Philadelphia Academy, though not recog- 
nizing the identity of Hooker's S. junceum with either of his 
own new species of Nasturtium. Four years later, in the 
Torrey and Gray Flora, Nuttall seems to have consented to 
the placing of his two plants under Sisymbrium, and these, 
headed by Hooker’s S. junceum, form in that work a sup- 
posed group of three species of reedy Sisymbria credited to 
the northern Rocky Mountain plains and valleys. 
The Sisymbrium of our books, like some other large con- 
ventional genera of Cruciferz, is absurdly heterogeneous, 
neither really defined by any author, nor possible to be de- 
fined until, by judicious exclusions, a truly definable and 
naturally delimited group shall alone be left in possession 
of the name. Sisymbrium, as we have it, has very long been 
a sort of convenient general receptacle for almost any sort of 
new siliquose crucifer which, though in need of an allotted 
place, may not by habit or marked character suggest affinity 
for Arabis or Brassica or Cardamine, or some other. 
