473 
mersed leaves very delicately filiform,” some of those in the plate 
being over two inches in length. These are exactly the leaves of 
P. diversifolius, Raf. (P. hybridus, Michx.), and unlike those of 
_ Spirillus which are much shorter and broader. The only spikes of 
fruit shown are emersed ones which are figured as sessile. Now 
neither diverstfolius nor Spirillus ever has emersed sessile spikes, 
but they are on peduncles from two to nine lines in length, and 
usually several times longer than the submersed ones. No Potam- 
ogeton answering to this figure in all respects has, so far as I 
know, been detected since Barton’s day either in New Jersey, his 
locality, or anywhere else in the United States. New Jersey has 
.been pretty thoroughly searched from one end to the other, and 
we should have been very likely to have seen this erratic form 
were it there. I am compelled to believe that in spite of his as- 
sertion to the contrary, Barton really had some form of Michaux’s 
hybridus in hand. In the course of his article Mr. Bennett makes 
a fling which is unworthy of him, and which I have most certainly 
done nothing to provoke. He says (p. 295): “but the ‘law’ that 
is desired to be forced on us, ‘that any species or variety that has 
been so named under any other species or variety cannot be used 
in the same genus,’ will be of somewhat difficult application. 
Students certainly will never know, and even monographers 
will not be safe, as proved by Dr. Morong’s own work, where 
he must (by his own law) change the names of at least three of 
his species, having failed to ascertain that they were in use before.” 
Mr. Bennett seems to hold me responsible for this “ law,” whereas 
it is a rule of nomenclature adopted by our National Association 
of botanists at their meeting at Madison last August, a meeting 
at which I was not present, and did not influence in the least. I 
certainly do approve of it as a good rule, under what is termed the 
law of priority, a law which Mr. Bennett himself must acknowledgé 
as sound, or his anxious search after the earliest names is useless. I 
think it would be difficult for Mr. Bennett to show that American 
botanists have ever manifested a desire to force this or any of 
their rules in nomenclature upon anybody either in this country 
or abroad. Certainly we shall lose no sleep if our British cousins 
choose to follow a different set of rules. 
