340 APPENDIX 



Experiments with Hybrids of other Species of Plants 



It must be the object of further experiments to ascertain whether 

 the law of development discovered for Pisum applies also to the 

 hybrids of other plants. To this end several experiments were 

 recently commenced. Two minor experiments with species of 

 Phaseolus have been completed, and may be here mentioned. 



An experiment with Phaseolus vulgaris and Phaseolus nanus gave 

 results in perfect agreement. Ph. nanus had, together with the 

 dwarf axis, simply inflated, green pods. Ph. vulgaris had, on the 

 other hand, an axis 10 feet to 12 feet high, and yellow-coloured 

 pods, constricted when ripe. The ratios of the numbers in which 

 the different forms appeared in the separate generations were the 

 same as with Pisum. Also the development of the constant com- 

 binations resulted according to the law of simple combination of 

 characters, exactly as in the case of Pisum. There were obtained 



The green colour of the pod, the inflated forms, and the long axis 

 were, as in Pisiim, dominant characters. 



Another experiment with two very different species of Phaseolus 

 had only a partial result. Phaseolus nanus, L., served as seed 

 parent, a perfectly constant species, with white flowers in short 

 racemes and small white seeds in straight, inflated, smooth pods; 

 as pollen parent was used Ph. multiflorus, W., with tall winding 

 stem, purple-red flowers in very long racemes, rough, sickle-shaped 

 crooked pods, and large seeds which bore black flecks and splashes 

 on a peach-blood-red ground. 



The hybrids had the greatest similarity to the pollen parent, but 

 the flowers appeared less intensely coloured. Their fertility was 

 very limited; from seventeen plants, which together developed 

 many hundreds of flowers, only forty-nine seeds in all were obtained. 

 These were of medium size, and were flecked and splashed similarly 



