in Hybridisation 47 



however, a constant character for each, in so far that healthy 

 plants, grown in the same soil, are only subject to unim- 

 portant variations in this character. 



In experiments with this character, in order to be able to 

 discriminate with certainty, the long axis of 6 1 ft. was 

 always crossed with the short one of f ft. to 1 J ft. 



Each two of the differentiating characters enumerated 

 above were united by cross-fertilisation. There were made 



for the 



1st trial 60 fertilisations on 15 plants. 



2nd 58 10 



3rd 35 10 



4th 40 10 



5th 23 ,, 5 



6th 34 10 



7th 37 10 



From a larger number of plants of the same variety only 

 the most vigorous were chosen for fertilisation. Weakly 

 plants always afford uncertain results, because even in the 

 first generation of hybrids, and still more so in the sub- 

 sequent ones, many of the offspring either entirely fail to 

 flower or only form a few and inferior seeds. 



Furthermore, in all the experiments reciprocal crossings 

 were effected in such a way that each of the two varieties 

 which in one set of fertilisations served as seed-bearers in 

 the other set were used as pollen plants. 



The plants were grown in garden beds, a few also 

 in pots, and were maintained in their naturally upright 

 position by means of sticks, branches of trees, and strings 

 stretched between. For each experiment a number of pot 

 plants were placed during the blooming period in a green- 

 house, to serve as control plants for the main experiment 



lessly took to have been an inch, but the translation here given is 

 evidently correct.] 



