212 
be the little known Hypericum Canadense var. minimum,* a plant 
which had never been well understood, but which, on account of 
its narrow leaves, had been associated unhesitatingly with /7. 
Canadense. Now, however, the study of a full series of specimens, 
collected at York Harbor in August, shows clearly that, though 
in one of its forms the plant certainly bears a strong general re- 
semblance to forms of H. Canadense, its real affinity is with 7. 
mutium, to which, indeed, it is nearly allied. Certain noteworthy 
differences, however, forbid its direct reference to that species, 
and give it an identity which is unmistakable when once the plant 
is understood. These differences, moreover, prove to be constant 
over a wide area; at least there is nothing to discredit them in 
specimens which show the plant to have an extensive distribution, 
ranging along the coast and islands of Maine into Nova Scotia, 
and westward through Canada. That it also extends southward 
in the mountains is attested by a specimen from Luzerne county, 
Pennsylvania, and one from ah elevated station in northern New 
Jersey. . 
It is to be noted of this New Jersey specimen that it shows : a 
near approach to muzi/um and may, perhaps, be taken as presump- 
tive evidence that the two plants intergrade. If such be the fact, 
however, it is, after all, only a part of the complementary fact that 
elsewhere the same plants have reached a condition of complete 
separation. The sub-species of one region has become a full 
species elsewhere in its range. 
In cases such as this of complete differentiation in one region, 
how are we to deal with intergradation in another? It is practicable 
to recognize a plant at the same time as a variety and as a species 
according as to whether it occurs in one or in another part of its 
habitat? It can only be said that if this condition of things 
exists in nature we cannot refuse to recognize it, and shall have to 
adjust our methods to it as best we may. But while we cannot 
dissect the facts of nature too delicately for certain purposes of 
botanical study, for other, more general purposes, we can often 
reach better practical results with duller tools. For general pur- 
*Dr. Britton has since shown that the name minimum of Choisy is not properly 
applicable to this plant, and has therefore designated it ve ‘pericum, Canadense vax. 
boreale. Bull. Torr. Club, 18: 365. 1891. 
