478 



THE AMEBIC AX NATURALIST 



[Vol. XLTX 



other lias only sixteen chromosomes. The form with 

 thirty-four chromosomes is apogamous and reproduces 

 without fertilization, but that one must not conclude that 

 apogamy is necessarily associated with a double or an in- 

 creased chromosome number, is clear from the case of 

 Rumex. Rum ex was investigated by Roth; one species, 

 R. co yd if alius, having* forty chromosomes as its 2N num- 

 ber, required fertilization to produce offspring; another 

 species, with only sixteen chromosomes, was apogamous. 



A short list of nearly related species or species with two 

 varieties varying in their chromosome numbers with their 

 character differences, if present, is given below. 



What conclusions can be drawn from these facts ? Cer- 

 tain botanists have attempted to connect chromosome 

 doubling with apogamy, as usually the chromosome num- 

 ber in apogamous species is higher than in the normal 

 species of the same genus; but there is no evidence of 



