OUR AMPHIBIOUS PERSICARIAS 239 
no terrestrial phase in that it is always a sterile one. In other 
words, P. ammophila is a normal terrestrial and P. fluitans and 
perhaps P. canadensis also normal aquatics. I wish to lay special 
stress on these facts; because at present it affords the best means 
of distinguishing all our various amphibious Persicarias from one 
another, especially when we find they have phases that closely 
resemble one another respectively, though always different 
beyond a doubt in at least one of them. ‘The classification of 
these plants must therefore take account of the fact that the 
plants with similar phase or phases; but different in another or 
others, may be distinct, or as I have already intimated, we are 
logically forced to accept the other alternative that there is but 
one amphibious smartweed which is to be called P. amphibium 
Linn., and that the others are not even varieties; for all have the 
same reason for being either recognized or rejected. In fact what 
is called P. emersa or P. coccinea has less reason for recognition 
than most of them. 
SUMMER AND FaL_ Aguatic PHASE. Perfect aquatic leaves 
scarcely distinguishable from those of P. canadensis or P. fluitans, 
purple only in spring, or early summer. Stems wiry, internodes 
at times 9.5 cm. long. Leaves elliptical-oblong to perfectly ellip- 
tical, obtuse or acutish at the apex, always cuneate at the base: 
petioles 1-2.5 cm. long. Leaves glabrous, shining, slimy especially 
when young, typically without spreading margins to the ochrea 
which is membranous. 
As already stated, to P. ammophila is distinguished from 
P. canadensis and P. fluitans in that it never blooms in the aquatic 
form but it soon emerges from the shallow water and becomes 
a riparian form, whch has the upper foliage terrestrial in character. 
In this phase it blooms occasionally, but, about the time of flower- 
ing its chosen habitat has dried up,:and the plants have all become 
terrestrials. It then produces one or two densely-flowered and es- 
pecially densely-fruited spikes, that resemble those of P. canadensis 
in shape, with the exception that the parts are all more or less 
glandular pubescent or simply pubescent. 
The water of the pools in which P. ammophila grows never 
dries up completely, there being usually a very deep and rather 
large part in the middle. The plant, however, clings to the shore 
where the water has dried up during part of the season, and the 
middle part is always left without any plants whatever. P. flwitans 
