24 AMERICAN MIDLAND NATURALIST 
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the low land along the stream is flooded. The roots of the Per- 
sicaria were then below water during the spring freshets and natur- 
ally developed the long stems of the floating aquatic stage. The 
associated Marsilia vestita too comes out then. The water rapidly 
lowers in July and August and after the low water mark has been 
reached in August the flowers of the Persicaria appear while the 
long stranded stems of the former floating aquatic phase are spread 
on the arid sand. The sterile terrestrial shoots after a while 
appear from the base of the aquatic stems, and not infrequently 
on them, but in this case only at the nodes where they happen to 
strike root. The probable reason why no aquatic persicaria 
stage was found in the water at low mark is that the shoots always * 
sprout in spring, and when the water at that point is too deep for 
the branches to reach to the surface. The conditions near St. 
John’s, Oregon are essentially the same regarding the plant, except 
that there is a large low stretch of meadow between the river and 
the plants which is submerged in spring. 
It will be seen that the ecologic study of the amphibious 
Persicarias is absolutely necessary before we shall be able to say 
the final word concerning their taxonomical relations. It was 
probably due to lack of sufficiently observing these plants and 
studying them untiringly in their native habitat that we have 
not the knowledge of this difficult group which we ought.to have 
at present when a new impetus has moved many to specialize 
in ecologic research. 
OUR WINTER BIRDS. 
BROTHER ALPHONSUS, C. S. C. 
The winter of 1909-1910 was long but not very severe. Snow 
covered the ground for three months. Only for a short time, 
early in December and January, the temperature went below zero. 
The winter proved a poor one for birds—few species appeared, 
and of these, most were seen but rarely. The continual snow 
that covered up everything may have been one reason for the great 
scarcity of birds. 
But the writer was unable to account for the total absence 
