208 Inheritance in Kicinus communis, L. 



numbers being 1108 bloom : 377 no-bloom). In F^, seeds from unguarded F^ plants 

 without bloom produced only plants without bloom. Seeds from unguarded F^ 

 plants with bloom either bred true in F^ or gave 3 bloom : 1 no-bloom families. 

 In one cross of bloom x no-bloom, the F^ plants had bloom, but were only lightly 

 covered as compared with their "bloom " parent. In F^, the plants approximated 

 a ratio of 3 bloom : 1 no-bloom as usual, though many of those with bloom were 

 lightly covered as in Fi. 



The present writer (1918), in a short preliminary note, put forward 

 the results of one cross between bloom and no-bloom. The F^ was 

 intermediate and in F^ 331 bloom and 118 no-bloom were obtained. 

 From these results it was considered probable that the presence and 

 absence of bloom in Ricinus constitute a Mendelian pair of characters. 



The Experimental Results. 



Further results are presented below on the mode of inheritance of 

 bloom, in crosses of bloom x no-bloom. 



The cross St Vincent Native Type 2 x Ridniis communis var. Oibsoni. 

 Bloom No-bloom 



The F^. Fourteen plants were grown. All possessed bloom, but 

 were lightly covered in comparison with the bloom parent. 



The Fz. Families were grown from all the fourteen F^ plants. Segre- 

 gation took place into bloom and no-bloom. During the examination it 

 was established that some plants could not be classified correctly until 

 the fruiting stage, as bloom was only present on the stem of the flower- 

 ing spikes. To distinguish between the various types of bloom proved 

 to be difficult in practice, and on this account the plants were divided 

 only into the two broad classes, bloom and no-bloom. 



