STOUT A1STD SU8A, CHROMOSOME IRREGULARITIES 27 



suggest the poisonous or toxic actions of foreign proteins in colloidal 

 relations. 



In the somatic and the pollen mother cells of plants of the Europa 

 clon there is normally a numerical equality in the two sets of chromo- 

 somes and there are no noticeable differences in the size and the shape 

 of the chromosomes. The incompatible relations develop as inherent 

 qualities of chromosomes that are balanced as to number. Yet there 

 are fragmentations of chromosomes, failure of pairing, non-distribution, 

 non-disjunction, division of univalents both in the first and in the second 

 meiotic divisions, the formation of abnormal shapes in chromatin units, 

 and the irregular formation of spores as to size, number and chromosome 

 complement. Finally there is abortion, death or a non-functioning for 

 nearly all of the sporogenous tissue. The fact that few functional mic- 

 rospores and macrospores are formed is, perhaps, an indication that only 

 in a few cases do the chromosomes find themselves in mutually har- 

 monious relationships as to number, form, complement, chemical and 

 physical interactions, and perhaps relative position similar to those 

 which existed in the gametes which united to make the individual plant 

 from which the clon has been propagated asexually. 



BIBLIOGRAPHY 



Arber, Agnes. 



1920. Studies on the binucleate phase in the plant cell. Jour. Roy. Mic. 

 Soc, 1920, pp. 1-31. 



Belling, John. 



1914. The mode of inheritance of semi-sterility in the offspring of cer- 

 tain plant hybrids. Zeit. fur induktive Abstammungs und Verer- 

 bungslebre, XII, pp. 303-342. 



1925. Chromosomes of Canna and Hemcrocallis. The Jour, of Heredity, 

 XVI, pp. 465-466. 



Blakeslee, A. F., and Cartledge, J. L. 



1927. Sterility of pollen in Datura. Mem. Hort. Soc. N. Y., Ill, pp. 

 305-312. 



Blaringhem, M. L. 



1928. Sur la fecondite de 1'Hemerocalle fauve (Hemerocallis fulva L.) . 

 Compt. Rendus, Acad. Sci. Paris, CLXXXVII, pp. 187-189. 



Bridges, C. B. 



1913. Non-disjunction of the sex chromosomes of Drosophila. Jour. 

 Exp. Zoology, XV, pp. 587-606. 



