FECUNDATION DEPENDING ON CONSTITUTION. 399 



affinities of the parents. The most striking and 

 unanswerable proof of this fact was afforded by the 

 genus Crinum, which is spread round the whole belt 

 of the globe, within the tropics and a certain distance 

 from them, under a great variety of circumstances, 

 affecting the constitution of individuals, which 

 nevertheless readily intermix by human agency. 

 Crinum Capense impregnated by either Crinum 

 Zeylanicum or Scabrum, produced offspring which, 

 during sixteen years, proved sterile, probably because, 

 notwithstanding their botanical affinity, the first is 

 an extra-tropical aquatic plant, and the latter two 

 tropical plants which affect dryer habitations, and 

 readily rot, at least in this climate, in a w^et situa- 

 tion." And yet this same plant, impregnated with 

 others which were swamp-plants, yielded fertile 

 crosses ; and the two which were extra-tropical pro- 

 duced a more fertile offspring than one extra-tropical 

 and the other tropical. 



The constitution of the offspring will be more or 

 less like that of both parents. Thus, if it is desired 

 to give hardiness to the offspring of a tender fruit, 

 and it is impregnated with the pollen of a hardy 

 sort, there is every probability that, while it will 

 endure the climate, it will be more sensitive to 

 severe extremes, which would not injure its hardy 

 parent. Mr. Herbert states that to obtain any pe- 

 culiarity in the corolla, the parent which has it 

 should be used as the male, and its pollen fertilize 



