H4 MAIZE 



CHAP, glumes on the cob may be blood-red or white. Forms inter- 

 mediate in colour occur, but this may be the result of cross- 

 pollination. As a rule, colour of cob is a fixed characteristic 

 of a breed, e.g. in true Hickory King it is always white. 

 White-grained breeds should have white cobs ; coloured chaff 

 discolours the mill-products. 



85. Number of Rows of Grain. — The rows of grain on 

 a cob vary in number from four to about forty-eight, but as 

 a rule they range from eight to twenty in the breeds grown 

 in South Africa. We have met with four-row and six-row 

 ears, but these appear to be due to some abnormal condition, 

 which has retarded the development of some of the rows. Odd 

 numbers of rows occur very rarely ; such irregularity is prob- 

 ably due to injury of one of the spikes of carpels during the 

 stage of development. It often happens that a pair of rows 

 fails to develop fully, both rows stopping short without reach- 

 ing the apex ; this may, perhaps, occur to only one of a pair 

 of rows (Fig. 83B). Sometimes one or two rows on one side 

 of an ear fail to develop through lack of pollination (Fig. 62), 

 probably owing to the silks having been unable to protrude 

 properly. Ears are sometimes found in which the grains are 

 so scattered that the number of rows cannot be traced (Fig. 

 84A) ; sometimes this breaking up of the rows occurs through- 

 out the whole ear ; and sometimes it is confined to one part 

 of the ear, most commonly to the butt. 



Each breed has its characteristic number of rows, e.g. 

 Hickory King has 8, Louisiana Hickory 10, Hickory Horse- 

 tooth 12, Arcadia Sugar-maize 12, Black Mexican 8. 



In some breeds, however, the number of rows is not yet 

 definitely fixed, e.g. Iowa Silver-mine, as grown in South 

 Africa, has 14, 16, or 18. This is, perhaps, due to crossing 

 with other breeds or with different strains of the same breed. 

 In some cases the percentage of a given number of rows is 

 found to be distinctly higher than in others, as shown by the 

 following cases, which suggest crossing : — 



