388 THE WHEAT PLANT 



in the manner suggestive of a perennial grass. In height and thickness 

 the culms are intermediate between the two parents. 



The ears are long and narrow, frequently longer and having more 

 spikelets than either parent. The empty glumes are elongated, inter- 

 mediate in width, strongly keeled to the base, and toothed or scabrid 

 along the keel like those of rye, but they possess more than one nerve, 

 and the spikelets are many flowered, like those of wheat. 



The absence of beards and the pubescence of the glumes are dominant 

 characters in these hybrids. 



In Tschermak's experiments Squarehead, Theiss, and Banat wheats 

 were used as the mother plants. Jesenko employed Loosdorf Bearded, 

 Bokhara, Velvet Squarehead, Red Galician, Epp, and other kinds of 

 wheat. 



Although in general features all the hybrids closely resemble each 

 other, the specific characters of the particular form of mother plant from 

 which they are descended are clearly recognisable ; but in cases where 

 different forms of rye are used as the male parent, their influence is not 

 visible. 



At the time of flowering the glumes open widely, and usually remain 

 separated from six to eight days. The anthers do not dehisce, and con- 

 tain mostly shrivelled and imperfectly formed pollen grains of variable 

 size, with occasional transparent round grains smaller than those of 

 either parent. 



Jesenko and Nakao found that the formation of the tetrads from the 

 pollen mother-cells was irregular, each of the latter being sometimes 

 divided into 3, 5, 6, or more degenerate cells. 



According to Nakao the larger pollen grains of the hybrid have many 

 more than the normal haploid number (8) of chromosomes of the parents, 

 the smaller ones less. 



In regard to the fertility of wheat x rye hybrids, Tschermak and 

 Nakao found the F 1 quite sterile, and Jesenko obtained negative results 

 from more than 3000 flowers pollinated with the hybrid pollen. Carman, 

 however, harvested 19 grains from 10 ears of one of his F l hybrid plants, 

 presumably self-pollinated, and from these grains obtained 14 F 2 plants 

 with 107 very variable ears. Among the plants of the F 3 generation were 

 some bearing ears 7 inches long, others with ears only 2 inches long or 

 less. The form of wheat Rural New Yorker No. 6, still grown in the 

 United States, is said to be a descendant of one of these wheat x rye 

 hybrids. 



Rimpau, in 1888, harvested fifteen grains from the F x plant of the cross 

 Red Saxon " Landwheat " x Schlanstedt rye grown under a net near a 

 hybrid wheat : it is not known whether they were the result of self- or 

 cross-fertilisation. The F 2 generation, like that obtained by Carman, 



