324^ 



NATUEAL SELECTION. 



[Ch. XXXVII. 



commonly called allied species, as to make tlieir origin a 

 cnrions subject of enquiry. He considered how far hybri- 

 disation could explain the enigma, and having his new dis- 



covery 



■most m his mind 



was disposed to exaggerate the extent to which that cause 

 ht have been efficacious in originating new forms. Hy- 



mig 



brids, he says, are not always sterile, and not only species, but 

 even o-enera, may have arisen from this source.'^ But in a 



'Teat many instances, when he speaks of one species being 



om 



which inhabit distant countries, ' sisters,' as being of common 



■ms 



tlieir first origin from one and the same som^ce, he is evidently 

 si^ecnlating on the origin of species by variation. In this 

 spirit he avowedly groups many forms of OpJirys^ Valerianella, 

 Myosotisy MecUeagOy and other genera under single collective 

 specific names, because, he says, after a comparison of a great 

 number of them, all the forms will be seen to have had their 

 origin from one source. He even throws out the idea 

 that the day may come when botanists may hold that all 



same p*enus mav have spruno- trom 



t 



The occurrence of some hybrids in a state of nature is 

 admitted by all botanists, although they are rare. Gentcmrea 

 hyhrida is produced, according to Herbert, by the frequent 

 intermixture of two well-hnown species of Centaurea ; but this 

 hybrid race never seeds. Rammcuhis lacerusy also sterile, has 

 been produced accidentally at Grenoble, and near Paris, by 

 the union of two ranunculi; but this occurred in gardens.]: 

 Mr. Darwin has lately (in the summer of 1867) satisfied him- 



between 



iment that the common 



primrose 



and coAVslip, and these two last ho 

 considers to be distinct species. Mr. Herbert, in one of Ins 



'Novas species, imino ct genera ex and Loveii, have kindly pointed out to 



copula diversariim specierum in Eegno 

 Yegetabili oriri/ etc. — Amoen. Academ. 



me these and many other passages m 

 which Linnsens shows that he had freely 



orig.ed. 1744, ed. Holm. 1749, vol. i. p. 70. speculated on the variability and trans 



mutation of species. 



t Hon. and Eev. W. Herbert, Hort 



f ' Tot species dici congeneres quot 

 eadem matre sint progenitye.'— Amceni- 

 tatesAcademicse, vol. vi. p. 12. Twoemi- Trans., vol. iv. p. 4L 



ncut Swedish naturalists, Professors Fries 



C^ 



S^ 



trieS; 1 



rise 



to 



Boi 



on 



the va 

 heads 

 formec 



shovr 1 

 dh'ers: 

 regarc 



witho 



specie 



may 1 



specie 

 may I 



lio^v a 



specie: 

 larcliei 

 same 1 



produc 

 admit 



crossiL 



Ihei 



'ee 



cannot 



tio 



i^. ai 



this 



pa 



{ 



^■aviati 

 ^ioii of 



