QUERIES IN LOCAL TOPOGRAPHICAL BOTANY. 127 
Darwin in argument against the belief in an essential difference 
existing between species and varieties. That hybridism does pre- 
vail, and this naturally, in some genera of plants, is not to be 
questioned ; but that any long perpetuation of a hybrid race by 
seed-renewal is possible is, I think, to say the least, open to very 
grave doubt. In some cases we know an inability to produce seed 
at all, in others, a want of power to impart the vital principle to 
it when formed, attaches to hybrid plants. On the other hand, it 
must be admitted that records do exist of certain hybrid races 
having been perpetuated for several generations. So long ago as 
1852 Dr. Bell-Salter inserted in the fourth volume of the Phy- 
tologist an account of some experiments he had made with the 
view of testing the power of seeds produced by flowers of Epilo- 
bium tetragonum (very possibly the modern obscurum), fertilized 
with pollen from those of E. montanum, to germinate. He says, 
" Seeds were easily obtained, and the hybrid plants produced were 
intermediate in all their characters between the parent species." 
" I saved seeds," adds Dr. Salter, " from the original hybrids, and 
sowed them. The second race was undistinguishable from the 
first. The seeds of these I again saved and sowed, and still no 
difference could be detected, and so on to four turns, when, being 
satisfied of the reproductive powers of these hybrids, and the per- 
manence of the form, I discontinued the experiment." "The 
original hybrid plants," he says, " were all of them almost exactly 
alike, one or two only out of a very large number having a slightly 
stronger resemblance to one of the parents. So with the subse- 
quent generation ; they remained like each other, and like the first 
race, with an occasional slight exception, as at the first." These 
experiments of the doctor's are far from being satisfactory, looked 
at by the light of to-day; for he would seem not to have taken 
any care to prevent the plants experimented on from being fertil- 
ized by pollen brought by insects or wind from other individuals, 
so they contrast remarkably with the carefully-conducted ones that 
Darwin so often brings before his readers, as carried out by him- 
self, for the purpose of testing the fertility of plants under varied 
circumstances. An accidental recross with one or other of the 
original parents might very possibly have occurred, and by its 
means a lengthened vitality of generative power might have been 
secured for the hybrid race. It is to be seen that Dr. Salter 
found some of the seedling plants showing traces of reversion to 
