24 LEAFLETS. 
SICARIA as agenus; though the Linnzxan notion has still seemed 
to prevail, doubtless for the most as a mere prejudgment, 
during the nineteenth century. 
Among earlier authors there are some who distinguished two 
genera, Persicaria with mild. and Hydropiper with pungent or 
peppery herbage; and the aquatic species were even again by 
some reckoned a distinct genus called Potamogeton. It is indeed 
almost certain that the real Potamogeton of ancient botany is 
Persicaria amphibia ; and on this account Bubani,in the Flora 
Pyrenza lately published, assigns the modern Potamogeton a new 
name. And so, it isa mistake on the part of Mr. Small in his 
new flora to have placed our native homologue of P. amphibia 
first in his list of the species, as if it were typical of Persicaria ; 
for it is not. P. maculosa, for which Mr. Small has coined a 
new and duplicate binary, is the type of PERSICARIA. 
The following members of the genus, formerly published by me 
under Polygonum, are here transferred: P. rustFoRMIS (Eryth. 
i. 259), OMISSA, FALLAX, ARCUATA (Pitt. v. 200, 201). 
Other North American species not hitherto transferred are 
P. cAREYI (Olney, R. I. Pl. 29), HARTWRIGHTII (Gray, Am. Acad. 
viii. 294), coccINEA (Muhl. iu Willd. Enum. 428), RIGIDULA 
(Sheld. Minn. Studies, i. 14), Lupovici1ANa (Meisn. in DO., xiv, 
116). This last Mr. Small may have failed to distinguish from 
Persicaria segeium,in the grammar of whose specific name he 
has also erred, supposing it to be an adjective, which it neither 
is nor can be made, except as segtalis. 
In the group of species of which the Old World Persicaria 
amphibia is typical I have at intervals, as opportunity was given, 
during years pursued field studies, and made copious specimens. 
with a view of revising it, at least as it is represented in North 
America; and I have long enough deferred the placing upon 
public record of certain important biologic facts observed by me 
in relation to these plants. 
All who have attained to even a superficial knowledge of their 
history are aware that the specific name amphibia was given to 
an Old World species because it was familiarly known to be 
amphibious, so to speak ; one form, or variety, as they called it, 
