176 ' " THE BOTAJSICAL/MAGAZim. :. ' '^^j ^^^ ^.^ 29^ 



or' at least Had a tendency to do so, as will be seen below; 

 and the number 9 in the red starch corn is looked upoii 

 as a result of the furthest reduction. Thus i should say that 

 all the races of ^ea Mays had once passed the stage of 12 

 gemini. Zea Mays tanicata or the pod corns whose kernels 

 are enclosed in husks and which were supposed to be the 

 nearest relative of the hypothetical ancestors, are most 

 desirable to be investigated in respect of chromosonle relations. 



The presence of two sets of gemini with respects to their 

 size and shape indicates that Zea Mays is a tetraploidal plants, 

 so that the haploid number of chromosomes must be originally 

 6. It is possible that the doubling of the original chromosome 

 number might have become in this plant a cause of the forma- 

 tion of so many races as we see now in Zea Mays. 



The more recent cytological investigations in plants have 

 revealed that in many cases the apogamic species have exactly 

 or approximately twice as many chromosomes as their closely 

 allied sexual species. It is further interesting to note that the 

 apogamy occurs generally hand in hand with polymorphism. 

 Strasburger says (8, P. 430), ** Starke Mutation, nur wenn 

 sie mit Chromosomenvermehrung zusammengeht, Ooapogamie 

 fordert." After Gates (I) it is not impossible that Oenothera 

 gigas which has double number of chromosomes in comparison 

 with Oenothera Lamarckiana is an apogamic plant, and 

 Strasburger (8, P. 411) is also inclined to hold the same view. 

 At present, however, there is no direct evidence that Zea Mays 

 also represents an apogamic plant. Moreover it is probable that 

 it is not the case. When I experimented upon ' Amber rice pop 

 corn ' and enveloped twelve ears with parchment paper to 

 avoid pollination, I got no ears with the kernels except two, 

 each of which was loaded with only one kernel which has 

 been likely produced by the normal process of fertilization. 

 From this I am rather inclined to think that Zea is a tetra- 

 ploid, but not an apogamic plant. 



Finally, the exact relations between the morphological and 

 physiological general race characters and the specific chromo- 

 some features amons^ different races were most desirable to be 



