206 AMERICAN MIDLAND NATURALIST 
the latter upon the drier bank close by! Had I not found all these 
indubitably connected I should not have hesitated for a moment 
in calling the aquatic phase P. mesochora. This is but another 
instance to show how futile it 1s to gather or study these plants 
without obtaining all the phases, and being positively sure of their 
connection, and selecting all the variable specimens that exhibit 
notable differences even in one colony. Nay more, in spite of the 
remarkable resemblance of the aquatic phases of P. mesochora, 
and P. coccinea it is to be remembered that no two members of 
the group could be more different from one another, except perhaps 
typical P. Hartwrightw itself. Now as P. mesochora possesses 
the herbaceous spreading tips of the ochrea and narrow leaves 
in its sterile terrestrial and spring plants so characteristic of P. 
Hartwrightu, one can readily see that such characters though 
quite valid as distinctions, are to be used only when one is perfectly 
sure of the phases of the plants in which they are found. By 
virtue of the character above mentioned P. mesochora belongs 
to the Hartwrighttanae as a group. It does not therefore belong 
to the same group as P. coccinea, nor has any very close relation- 
ship to it; for the latter never in any of its phases, terrestrial, 
aquatic, or even spring sterile terrestrial, has been found to have 
spreading herbaceous borders to the ochreae. 
Not only does P. coccinea resemble P. mesochora in the aquatic 
so closely as to be difficult to distinguish, but I have found at 
times among the ordinary broad leaved blooming terrestrial 
phases of the former, plants in flower with the narrower leaves 
of P. mesochora as the latter grows typically in the terrestrial 
phase. Such plants I have collected on the Virginia shore of the 
Potomac River at Plummer’s Island, growing as aberrant forms 
of P. coccinea, most of the plants being typical wide-leaved speci- 
mens of the latter. I must confess my inability to distinguish 
these aberrant forms from typical plants of flowering P. mesochora, 
as I have collected this at the lakes at Notre Dame, Ind., and 
described elsewhere as types of the terrestrial phase of the latter. 
And yet it is to be remembered that the spring plants of these 
two species could not possibly be confounded even in herbarium 
specimens. It is to be remembered, moreover, that typical P. 
coccinea or P. emersa in phases indubitably proved to belong to 
it, is practically indistinguishable from P. amphibia as the manuals 
understand the latter. It is to be remembered also that the real 
