210 



Inheritance in Ricinus communis, L. 



families but there is no marked deviation from expectation in F3 families 

 or in the back-crosses. 



2. Spines on the Capsule. 



A variety of Ricinus devoid of spines on the capsule was collected in 

 the Grenadines. It bred true on being grown in pedigree culture. 

 Grisebach (1864) records this variety under the name inermis. 



In a cross between spiny and spineless the following results were 

 obtained : 



The Fi. The fourteen Fi plants were spiny, though the number of 

 spines per capsule was obviously less than in the spiny parent. Spini- 

 ness is therefore incompletely dominant. 



The F^ Families were grown from all the F^ plants. The results 

 are presented below. 



The Fg. Of 17 families grown from F2 plants which were spiny, 5 

 bred true (219 plants). 



Twelve families segretated into spiny and spineless. 



