CHAP. VI. HYBRID PLANTS. 287 



vents their reciprocal fertilisation, so does this obstacle, of 

 whatever nature it may be, in general present an insuperable 

 bar to the intercourse of different genera. All the stories 

 that are current as to the intermixture of oranges and pome- 

 granates, of roses and black currants, and the like, may, there- 

 fore be set down to pure invention. 



It is, nevertheless, undoubtedly true that bigeners, that is to 

 say mules between different genera, have in some few cases 

 been artificially obtained. Kiilreuter obtained such between 

 Malvaceous plants ; Gaertner, between Daturas and Henbane 

 and Tobacco ; Wiegman, between a Garden Bean and a Lentil ; 

 and there ai-e other well-attested cases. But all such produc- 

 tions were as short-lived and sickly as they were monstrous. 



By far the best series of observations that has been instituted 

 with a view to determine the laws of hybridism was that of 

 Kolreuter, who, about the year \llb, commenced a set of 

 experiments, which he continued to prosecute for twenty 

 years, upon species of the genera Digitalis, Verbascum, Sola- 

 num, Malva, Linum, Dianthus, and Mirabilis. It is upon 

 those experiments, combined with the subsequent experience 

 of others and my own observations, that the foregoing state- 

 ment has been made. 



It has, nevertheless, been asserted by divers experienced 

 cultivators of the present day, that the conclusions drawn 

 from the experiments of Kolreuter have been too hasty ; and 

 that, if they apply to the genera that were the special subject 

 of the attention of that observer, they are by no means appli- 

 cable to plants in general. It has been urged, in proof of this 

 statement, that many different species of African Gladioli, of 

 Pelargonium, of South American Amaryllis, of Crinum, of 

 Triticum, &c., breed freely together, and that their seedlings 

 are as fertile as themselves. 



I must confess that these instances are by no means such as 

 to shake my confidence in the accuracy of the laws deduced 

 from Kiilreuter's experiments. In the first place, there is a 

 degree of vagueness and looseness in the cases that are 

 specified, which is particularly striking if compared with the 

 precision with which Kolreuter's experiments were conducted; 

 secondly, in all the instances above mentioned, which, I believe, 



