Sunshine, Rain, and Wind 
the identical climate which their ancestors have endured 
for many generations.’° But the environment may 
change altogether even in the same place. When, for 
instance, an open rough hillside is planted with young 
spruces, the conditions are entirely altered as soon as 
the trees become tall and bushy enough to overshade 
the ground. At first there may have been an abundance 
of grasses, quantities of red campions, foxgloves, blue 
bugles, brambles, and raspberry bushes, and in the more 
open places the dog violet (Viola canina). 
As soon as the young trees begin to close in over the 
soil, many of these plants vanish. The brambles and 
roses will try to become climbers, straggling over the 
branches. The campions and other herbaceous plants 
will not flower but produce runners or tubers of some 
kind. Dr. Krasan declares that under these conditions 
Viola canina becomes Viola Riviniana, but it is dangerous 
to agree with him, for most British botanists would 
emphatically protest. 
Such a thoroughgoing change as this affects every 
plant in the wood and even the young spruces them- 
selves. Many plants of the ground flora vanish or 
retreat into underground reserve stores. Of those that 
remain, none can be unaffected either in external form 
or in internal structure.” 
Even in one and the same valley there may be lime- 
stone outcrops or other special and peculiar soils, In 
that case one may discover closely allied species in- 
habiting the same valley, but keeping strictly to their 
own territory. Soldanella minima, for instance, occurs 
on chalk in central Europe, and S. pusilla replaces it 
on other rocks.. Such replacing species are supposed 
to be parallel forms derived from some common type. 
(The usual German term for such species is vicartirender, 
which might be best translated as curate species, for the 
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