niUOMOSOME NUMBERS AND THEIR ALTERATION 213 



NORMAL 



ROLLED 



GLOSSY 



BUCKLING ELONGATE 



ECHINUS 



COCKLEBUR MICROCARPIC REDUCED 



POINSETTIA 



SPINACH 



GLOBE 



ILEX 



Fig. IGO. — Seed capsules of iioriaal and primary tiisoniic types of the Jinisoii weed 

 (Datura stramonium). Each of the 12 members of the genome (see Fig. 72) produces a 

 cliaracteristic visible effect when present in triplicate. In "rolled" the extra member is 

 cnromosome 1.^, in "glossy" it is 3.4, and so on to "ilex" with 23.24. The plants show 

 other differences also. {Courtesy of A. F. Blakeslee.) 



