OUR AMPHIBIOUS PERSICARIAS 19 
near Hudson Lake. I was unable to collect specimens here. 
Farwell’s No. 593946 of U.S. Nat. Herb. collected near Detroit 
may be referred to P. mesochora. 
From both of the Notre Dame Lakes I have several times 
with considerable trouble obtained shoots having all the phases 
in one individual. The fact that the high shore or terrestrial 
phase never matures flowers seems to show that the plant is nor- 
mally aquatic. I have observed specimens of the terrestrial on 
what must have been the old shore line of the drained and lowered 
lakes at Notre Dame in 1843. Some years after the lowering of 
the water these plants were left high and dry in the grass, 50 feet 
or more from the present shore. They appear annually and the 
rootstocks even seem to spread. Only once or twice within the 
last five or six years have I observed a spike of buds which wilted 
invariably before reaching the flowering stages. It is undoubtedly 
P. mesochora and the patch is only a short distance from another 
on an island of the lake formed in the last dredging a few years 
ago. 
In another place near St. Mary’s Lake the terrestrial plant is 
usually mowed down in summer. The young shoots appear with 
spreading borders to the ochreae, which are absent in older growing 
plants at this time. This too is undoubtedly P. mesochora as 
it is but two or three metres from the shore where riparian and 
aquatic phases flourish, and where I collected specimens with all 
phases on one individual. Moreover, no other Persicaria grows 
anywhere around either of the lakes. I have watched all these 
plants during several seasons from spring till fall and studied the 
different stages in the development and transition of the phases. 
As has been noted in the description of the phases, matters are 
complicated even more by the fact that the phases themselves, 
especially the terrestrial in case of P. mesochora, vary somewhat in 
appearance from one part of a season’ to another, so that the ter- 
restrial phase looks quite different in summer and early fall from 
what it did in spring. Dr. Greene* has pointed out that our 
knowledge of the aquatic Persicarias will then of necessity progress 
slowly until botanists in their respective sections of the country 
begin to study carefully the variations of the plants under changing 
conditions throughout the year. 
* “Greene, EH. 'L. Leaflets; p. 25, 26. 
