June 19, 1916 Correlated Characters in Maize Breeding 443 



In the progeny of the reciprocal ears i and 2 there are no really signifi- 

 cant differences. The progeny of ear 3, however, which descended from 

 entirely different first-generation plants, shows a number of differences 

 from the remainder of the second-generation plants. 



Although the average height of the plants from all these ears is prac- 

 tically the same, the progeny of ear 3 shows smaller values for a number 

 of other dimensional characters. The number of branches, primary and 

 secondary, length of leaf, total nodes, length of glumes, and number of 

 rows of grains are all slightly lower. With the exception of length of 

 leaf and length of glumes, these differences might be interpreted as 

 indicating a more pronounced development of the Esperanza characters. 

 The same may be said of the exsert, which is higher in ear 3. In the 

 development of tuberculate hairs, on the other hand, the progeny of ear 

 3 was decidedly more like the Chinese variety. 



In addition to the measurements given in Tables II and III, there are a 

 number of differences that deserv^e to be more fully discussed. 



HAIRS ON THE LEAF SHEATH 



Perhaps the most striking difference between the varieties is the cov- 

 ering of the leaf sheaths. In the Chinese variety the leaf sheaths are 

 similar to those of the ordinary types of maize. The surface is smooth, 

 except for fine spicules, which occur especially over the fibrovascular 

 bundles. The spaces between the fibrovascular bundles are crossed by 

 numerous diagonal ridges or cross veins irregularly arranged and usually 

 discontinuous at the fibrovascular bundles. These cross veins with the 

 fibrovascular bundles cover the surface of the sheath with a coarse 

 reticulum. 



In the Esperanza variety the cross veins of the sheaths are absent or 

 confined to the seedling leaves, and the spaces between the bundles are 

 occupied by tubercles, each bearing a long hair (PI. LVIII). These 

 tuberculate hairs are absent from the sheath of the first six to eight 

 leaves of the seedling. They appear abruptly and may cover the entire 

 surface of the first sheath on which they appear. The hairs are from 

 3 to 5 mm. long, and the tubercle is approximately }4 mm. wide and of 

 the same height. 



In the Waxy Chinese variety tuberculate hairs are completely absent 

 (PI. IvVI, fig. 2). As in all varieties, there is a small area closely confined 

 to the throat of the sheath that is clothed with lopg hairs. It is not 

 clear whether these hairs are homologous to the tuberculate hairs of the 

 Esperanza variety or not. Even considering these hairs at the throat 

 of the leaf sheath in the Waxy Chinese variety as of the same type, the 

 two varieties are completely separated, \^dth not even an approach to 

 overlapping forms. In the hybrid and its progeny three methods of 

 measuring the degree of hairiness were employed: 



(i) By recording the total number of nodes with hairy sheaths. 



