n8 



THE WHEAT PLANT 



In the few cases in which I have been able to obtain reliable counts 

 the haploid number is 8 in T. monococcum, and 16 the diploid number in 

 some forms of T. vulgare. Larger numbers, not possible to count with 

 certainty, I have observed in somatic cells of other forms of T. vulgare. 



FIG. 97. i, Transverse section, 2, longitudinal section of a loculus of a Jtoung anther 

 ( x 210) ; a, epidermis ; b, endothecial layer ; c, " middle " layer ; t, tapetum ; p, pollen 

 mother-cells. 



Overton (1893) gives 8 as the haploid and 16 as the diploid number 

 in T. vulgare 



FIG. 98. i, Transverse section of anther-lobe, showing single ring of free pollen mother- 

 cells in each loculus ( x 100) ; 2, longitudinal section of a portion of the wall of the 

 anther (x 260) ; 3, surface view of cells of the tapetum (x 260) ; n, endothecium ; c, 

 " middle " layer ; b, tapetum; a, pollen mother-cells. 



Kornicke (1896) found 16 in the somatic cells and 8 the reduced number 

 in the embryo-sac and pollen mother-cells of T. compactum ; in one vege- 

 tative cell of the anther of the same plant he counted 24 chromosomes. 



The number observed by Dudley (1908) in the first division of the 

 pollen mother-cells of T. vulgare was 8. 



