OUR AMPHIBIOUS PERSICARIAS 223 
or slightly wider at the middle of the leaf, which is lanceolate 
to oblong of a bright green but later paler, and soon withering 
as the terrestrial foliage replaces the few aquatic leaves: petioles 
to oblong of a bright green but later paler, and soon witherings 
as the terrestrial foliage replaces the few aquatic leaves: petiole 
4-5 cm. long, slender; The upper terrestrial leaves are larger, 
longer 13-15 c. long 4-5 cm. wide acuminate, and rounded at 
the base, elliptic oblong or elliptic oval. The intermediate 
leaves are at first rounded, then cordate at the base and then 
change gradually to the normal terrestrial subcordate to cuneate. 
The intermediate leaves with cordate base are glabrous, but not 
slimy aquatic being emersed, and ‘are oval or ovate in shape. 
The petiole gradually becomes shorter as the leaves pass to-the 
terrestrial. hay tie 
What I may designate as type phases were. collected along the 
St. Joseph, South Bend, and Southern Railroad in St. Joesph 
Co., Indiana, between Lydick, Ind. and Galien, Mich. about two 
miles from the state boundary. They are nos. 923a (two sheets) 
and 923aab, and were gathered June 15, 1911. The plants are 
therefore sterile, and it may be inferred that the strictly aquatic 
phase of P. pratincola is vestigal, represented by only a few leaves 
at the base of such stems as are found near or in shallow water. 
Even if the water remains the stems elongate and later produce 
only terrestrial foliage. The species, therefore, like P. grand1- 
folia bears all the phases consecutively on one shoot, but differs 
in that the aquatic is the merest vestigial remains, to be looked 
for and found only when the plants appear early in the season, 
and when not yet blooming. Some strictly aquatic plants were 
found, but had only a few first leaves. The habitat of the plants 
was a stall pool only a few feet wide, evidently filled with water 
only in spring and early summer. It appeared as if it might 
once have been an animal wallow, though no animals could have 
been near for years as it was surrounded and invaded by rather 
old underbrush. The pool was in a field in low ground, and sur- 
rounded by normal terrestrial plants of P. pratincola, also present 
in my herbarium as Nos. 923 c, 923d, 923 de. No. 922 is another 
terrestrial found not far from this place. Other specimens of 
P. pratincola | may here refer to from the U. S. National Her- 
barium are the following. 
No. 230396, B. Finks Fayette Co., Iowa, VIII. 1894; 324300, 
