208 AMERICAN MIDLAND NATURALIST 
or be forced back to the original Linnaean idea of but one species. 
Whatever reasons the authors of the seventh edition of Gray’s 
Manual had for relegating P. Hartwrightii to the status of variety, 
Dr. Cowles* still maintains that it is the same as Polygonum 
amphibium, or only a ‘“‘hairy form”’ of the latter. From the brief 
references given to the two plants, one would infer that he is 
insufficiently acquainted with the plants to know what they really 
are. Infact P. Hartwrightw as Dr. Greene had shown, is by no means 
a plant “with leaves covered with numerous and stiff long hairs.” 
As a terrestrial phase or “form’’ at 1s quite smooth, and never has 
hirsute leaves even as a “land form.’ Dr. Cowles also seems to 
infer that the aquatic phase is the “‘typical’’ phase of the plant 
If it is meant that Linnaeus published this either without reference 
to terrestrial or knowledge thereof, the information is beside the 
point. From the description and drawing of the terrestrial “‘ Polyg- 
mum Hartwrightw,’ whatever that name means to the author, 
I would infer that he does not know what the real P. Hartwrightiu 
Gray is, for he actually described what Dr. Greene published 
as P. ammophila. Moreover, P. ammophila and P. Hartwrightw 
are as different from each other as P. amphbia is from P. 
emersa. Moreover, one remarkable fact, among others as im- 
portant and more so about the real P. amphibia, is that its 
terrestrial phase known for centuries in Europe has not 
‘spreading borders to its ochreae! ‘There is in fact no plant in 
Europe that has these, and just because the terrestrial of 
Europe and the various terrestrial plants of America which in 
no way resemble one another happen to have aquatic phases 
more or less as distinct as such, there is no conclusive reason for 
saying that P. Hartwrightii has been changed into P. amphibium. 
There may be a certain amount of mental amusement in juggling 
names, but for all that, it is the duty of the ecologist to see that 
they are applied to the proper things. “Nomina si nescis perit 
et cognitio rerum,” is a very old adage. There may be little in a 
name, but unless we are sure what is represented by it, the knowl- 
edge of phenomena and things may become a hopeless mess. Pre- 
sumably Dr. Cowles does not believe in the numerous species 
of Persicarias as outlined in the last few years, and if he does 
not accept even P. emersum, shown to have an aquatic phase 
more like the real P. amphibium of which it may be called a broad- 
* Cowles, H.C, Textbook of Botany. Vol, I, Ecology. pp. 574, 575. 
