1895.] A Reply to Dr. Robinson’s Criticism. 165 
I fully agree with Dr. Robinson that the outcome he de- 
picts would be preposterous, and I take this opportunity to 
point out his error, feeling also some responsibility for not 
having made the case clear to him formerly. The phrase 
“once a synonym always a synonym” is unfortunate and mis- 
leading, and I have preferred to substitute for it in con- 
versation the equivalent phrase, ‘‘the rejection of homonyms.” 
The principle is simply this, that after a name has once been 
published, the same name shall not again be a valid designation 
for any other plant, even though the original name should 
meanwhile have become a synonym of some other still older 
name. For example, the name Bigelovia has been applied to 
five or six widely scattered genera, all the earlier of which have 
been referred toother still oldergenera. The rule of the rejec- 
tion of homonyms renders the name Bigelovia, therefore, un- 
available for the genus to which it has been applied in recent 
years, and the check-list consequently takes up the next older 
name, Chondrophora. The force of the rule may be illus- 
trated by the fact that by the old system, if any one of the 
€arlier genera named Bigelovia should at any time be re- 
vived, it would necessitate a change also in the name of the 
later and current Bigelovia. There are many cases in which 
under the old system the revision of a family and the conse- 
well. Under the new system a change in one generic name 
Can not affect any other genus. Moreover, quite the opposite 
of Dr. Robinson’s supposition, a restoration of the name Big- 
elovia would be perfectly valid, under this system, should the 
genus to which it was first applied be found really autono- 
Mous and therefore require a separate designation. 
It is to be regretted that Dr. Robinson did not, while at the 
Madison meeting, bring forward for discussion his questions 
as to principles, for they undoubtedly were well understood, 
