CONFIRMATIONS OF MENDEFS lAWS 



359 



starchy character dominates. When an egg-cell of the wrinkled 

 sugar-maize stock is fertilised by a pollen-cell of the round 

 starchy stock, the result is a round seed with starchy endosperm. 

 If this seed is sown, it becomes a plant which, on self-fertilisation, 

 forms a cob with a mixture of round starchy and wrinkled 

 sugary seeds in the ratio 3 : i. The wrinkled seeds yield sugar- 



4 ▲ 4 A 



fl iilliiii I* 



m DD OD D(R) 0(R) RR OD 0(RJ 0(R) RR. R^ Tr 



DD 



RR 



Fig. 38. — Diagram showing Mendelian phenomena in nettles, 

 permission of Prof. Correns.) 



(By 



P', leaves of the two parents ; D, Urtica pilulifera ; R, Urtica dodartii ; F% leaf of the 

 progeny, D(R), the serrated type being dominant; F", leaves of the hybrid's offspring ; iDD 

 + 2D(R) + iRR ; F ■, leaves of the next generation ; DD, pure extracted dominants ; RR, 

 pure extracted recessives ; D(R), impure dominants. 



maize ; the round seeds yield two " impure rounds " to one 

 " pure round." Correns has observed a very interesting case 

 in which two pairs of contrasted characters are imphcated. 



One variety, Zea mays alha^ which has smooth white seeds, 

 was crossed with another variety, Zea mays coeruleodulcis, 

 which has wrinkled Uue seeds. The hybrids (F^) had smooth 



