IN THE TBOPICS : III. 175 



There can be little doubt that had a precise examination of 

 every individual been substituted for the examination in mass 

 which was actually employed, the full explanation of the 

 complexities seen would soon have been discovered ; and the 

 result of such an examination would without doubt repay the 

 time expended upon it by any one situated in a suitable climate 

 who should be disposed to take the matter up, in the light of 

 Correns's results and of those detailed above. The results 

 already obtained are however sufficient to show that in all 

 probability there is here no exception to the ordinary course of 

 Mendelian segregation. 



It is to be noted that in the above descriptions the term 

 blue (or blacky is applied to all grains which showed any trace 

 of the blue (or black) character. The intensity of colour 

 varied considerably from grain to grain and in different parts of 

 the same grain, and it seemed not unlikely that in the case 

 of the cross with Black Mexican a definite factor for mottling 

 was concerned, and possibly a definite intensity factor as well. 

 These are points which might also be profitably studied by 

 the process of individual pollination. 



In the case of the mongrel flint corn a truly piebald 

 character made its appearance in about one per thousand of 

 the blue grains. Two piebald yellow and white grains were seen 

 among about 50,000 presumably heterozygote grains which 

 were examined. 



Finally attention may be directed to those curious cases, 

 exemplified in maize by the mealy and hyaline characters of the 

 endosperm associated respectively with the indent and flint 

 types of grain, in which characters of the endosperm (seed gene- 

 ration) behave on crossing as if they were characters of the 

 maternal plant. Other instances are seen in the indent 

 character of pea seeds (Tschermak), and in the soft and hard 

 endosperm of wheat grains (Biffen). Unlike the last mentioned 

 case the corresponding characters in maize do not show the 

 phenomenon of dominance, and owing to the great variability 

 of the cross-bred plants the existence of segregation is only to be 



9(8)06 li 



