26 
BULLETIN OF Wlf^CO.NSlX NATURAL HLSTOKY SOCIETY. VOL, 2. NO. 1. 
All the species mentioned so far one would not think of class- 
ing otherwise than as niesophytes. The next one, however, is 
quite distinctly xerophytic, although not extremely so. This is V. 
sororia, a species ver\' similar to V. obliqno, but distinguished by 
the pronounced hirsuteness of the green parts. It is perhaps the 
commonest species in this neighborhood, and invarably occupies 
dry localities, such as sunny hillsides or the hawthorn scrub lands. 
Hardly ever does one find this and its cousin, V. obliqiui/mtQrm'mg- 
ling, although it is common to see the latter flourish at the foot 
of a hill, where the ground is fairly moist and the insolation mod- 
erate, while the adjacent slope, dry and exposed to hot sunlight, 
shows numerous plants of V. sororia. Stations similar to those 
occupied by this species are pre-empted by • V. pedafa in many 
places a little farther west, for instance on deforested slopes of the 
Kettle' Range. The division of the leaves in this species seem 
to be a xerophytic adaptation, serving a similar purpose as the 
hirsuteness of V. sororia. 
In some places, c. g. near the Lake Shore in section 36, Town 
of Oak Creek, the last named species shares its dry habitat with 
Viola Lahradorica. But more often that species is found in the 
damp, almost swampy places in the forest, where elm, black ash 
and red maple indicate the great moisture content of the soil. Here 
the ground is often largely occupied by mosses, and among these 
the low, much-branching plants, with their tangle of thin, super- 
ficial roots and little pale flowers are found. The habit of this 
species forms a striking contrast to that of its mesophytic cousins, 
like V. Scahrhisciila or Canadensis. Where it grows copiously, it 
forms carpets on the ground, and might almost be called cespitose. 
In its neighborhood in such damp, mossy localities one is quite 
apt to find also the smallest of our violets, V. hlanda. Both of 
these species are distinguished for their small size. But the pecu- 
liarity of V. Lahradorica which is most interesting in the present 
connection is that it seems to flourish equally well in decidedly 
dry and pronouncedly wet situations. V. Lahradorica is closely 
allied to the European V. canina, in fact so closely that some tax- 
onomists will give it only varietal rank. (V. canina Muehlen- 
hergii.) Now the European form is found in very dry localities, 
such as gravel slopes where the dominant vegetation consists of 
xerophilous grasses like Fcstnca ovina, or among the heather. 
There must be something in common between the two apparently 
so very dififerent stations in which Viola Lahradorica is found, 
and that common quality must be something which favors xero- 
phytic adaptations. For the low growth and semi-cespitose habit 
of this species is a fairly pronounced indication of xerophily. 
