202 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
suppose that this Continent enjoys special facilities in this respect. Floral 
contrivances for promoting cross-fertilisation lead. to a constant trans- 
ference of pollen, for we know that insects in their search for food are 
indiscriminate in the flowers which they visit, and this circumstance 
leads to a constant origination of hybrids wherever allied species capable 
of intercrossing grow in close proximity. Their production is largely a 
question of opportunity, for,as we have already seen, some have originated 
spontaneously in gardens where allied species from different localities 
have been planted together. And there is Hrigeron Hubseni, a remark- 
able wild hybrid which has originated between the European perennial 
E. acer and the introduced annual EH. canadense, which furnishes an 
excellent example. 
Of these hybrids only a fraction survive and multiply. In the first 
place they may be sterile, or if fertile they are liable to he swamped by 
recrossing with the parent stocks. They may even be less suited to the 
conditions under which they find themselves than either parent. The 
establishment of a hybrid race is dependent on certain circumstances. It 
must be fertile with its own pollen—that is with pollen of the same 
hybrid stock—and it must be in harmony with the conditions of its 
habitat. It has to enter into a struggle with the species already there, 
and particularly with its parents, and only if as well or better fitted to its 
environment will it make successful headway. In a few cases, as we 
have already seen, it may grow apart from either parent, and encounter 
new conditions of soil cr climate which specially favour it. Under such | 
a combination of circumstances hybrids may become dominant, yielding 
hybrid races. 
Viewed from this standpoint the phenomena of hybridisation acquire 
a special significance to the systematist, and a knowledge of the behaviour 
of artificial hybrids under cultivation, and the relation they bear to their 
parents, should help him greatly in the identification of those which 
occur spontaneously in a wild state. And a correct idea of the existence, 
behaviour, and distribution of natural hybrids where their life is un- 
trammelled should throw further light on the very origin of species. We 
need not follow the subject into the regions of pure speculation, but if 
hybrid races exist in the present they may have done so in the past—a 
nice little problem for speculative geologists to tackle. 
A knowledge of garden hybrids, however, will not enable us to under- 
stand or recognise all those which occur in nature, and various problems 
will have to be investigated by direct experiment, the results of which 
will throw further light on a most important but perplexing and intricate 
subject. 
I think I have said enough to vindicate the opinion of Dean Herbert, 
expressed over three-quarters of a century ago, that hybridists would not 
confuse the labours of systematic botanists. Indeed, in the words of Mr. 
C. C. Hurst, “ artificial hybridisation, which it was supposed would lead 
systematic botany into the direst confusion, by the irony of fate.seems 
destined to be the only trustworthy means of saving systematic botany from 
its own confusion, and the systematist, however orthodox he may be, can 
no longer afford to ignore artificial hybridisation.” The foregoing facts, 
I think, fully warrant the conclusion. 
