130 PITTONIA. 
own rules? Certainly no rule relating to the observance of 
priority has been more generally recognized and deferred 
to than this, that a genus, as to its name at least, stands or 
falls with its type-species; no rule is more indispensably 
necessary; and nothing but endless change and confusion 
can come of the neglect of it. 
For such an un-Tournefortian and un-Linnzan Erysimum 
as that of all recent authors, the authorship seems to rest 
with Robert Brown, the elder De Candolle, and authorities 
of more recent times. But if we are to take generic names 
from Tournefort and Linnæus our Erysimum must consist 
of ERYSIMUM OFFICINALE, Linn., and its true congeners, if 
it have any. 
In my Manual of the Botany of the Region of San Francisco 
Bay I gave expression to the opinion that such plants as 
compose the type of Cheiranthus, Linn., and Erysimum, DO., 
form one natural genus notwithstanding that the pods of 
the one group are quadrangular and of the other flat. I did 
not know, at that time, that any author before me had given 
expression to the same idea; and I have been not a little 
surprised to see that in the Synoptical Flora, the same doc- 
trine, so entirely opposed to time-honored empiricism, is re- 
asserted. 
The Cheiranthus types had been received by Tournefort 
under his Leucoium, and were well removed by Linnæus; 
and it had been better to have retained for these the simple 
Arabie name Cheiri, a name which Adanson sought to re- 
store in place of Linnsus' Latinized alteration of it. Still, 
I think that Linneus has a right of priority in his name 
Cheiranthus, and that therefore it ought to stand. No one 
anterior to him had defined such a genus. I can therefore 
conscientiously, and in conformity to the all-important prin- — 
ciple of priority, propose the adoption of the following species 
under the CHEIRANTHUS genus-name. In looking into the 
bibliography of the species, I have been pleased with the 
discovery that Nuttall early in his botanical career prac- 
