S. C. Harland 211 



Three families were grown from F^ spineless plants. All bred true 

 (67 plants). 



Back crosses of F^ x Spineless. 



The above results indicate that the presence and absence of spines 

 on the capsule are a simple pair of Mendelian characters. The factor 

 for spines may be denoted by S, and its allelomorph by s. 



3. Colour of the Vegetative Parts. 



According to the observations of White (1918 b), stem colour in 

 Ricinus may be divided into five categories — bright green, green with 

 reddish blush on sunny side, carmine or rose red, mahogany red, and 

 purple (dark red). This author also states : 



Associated with the types of stem colouring are pigmented areas in other parts 

 of the plant. The mahogany red stemmed plants have mahogany red leaves and 

 fruits. The rose and red blush stemmed types have green leaves with red or reddish 

 midribs. The dark purplish-red (mahogany bloom) stemmed plants have dark 

 purplish-red leaves and fruits. 



His experiments may be summarised thus : 



1. Red-blush and green form an allelomorphic pair of characters. 



2. Red-blush" and mahogany are allelomorphic. 



3. Rose and red-blush are allelomorphic. 



The results of the present writer's experiments -svill now be given. 



1. The Cross Red-hlush x Mahogany. 



This cross gave results similar to those obtained by White. The Fi 

 was rose or carmine stemmed, and in F^ segregation occurred into 102 

 rose and red-blush, and 31 mahogany (expectation 103:34). 



The F3. A few families were grown in F^. 



Of 7 families grown from rose and red-blush F^ parents, 3 bred true 

 (25 plants). 



The remaining families segregated into rose and red-blush, and 

 mahogany. 



Joarn. of Gen. x 15 



