No. 631] SHORTER ARTICLES AND DISCUSSION 187 



filiate flowers in Coir and Sclrrachur, also produce androgyny 

 in the inflorescence of teosinte. This fact may be of some signifi- 

 cance. Maize was doubtless originally a tropical plant. How 

 much of its erratic floral behavior when grown in temperate lati- 

 tudes is due to real, fundamental differences between it and 

 teosinte, and how much to environment? 



It seems, then, that as to androgyny or as to protogyny of the 

 individual inflorescence, there is no fundamental difference be- 

 tween maize and the other American representatives of the 

 Maydese. "When this fact is coupled with a reduction in the num. 

 ber of inflorescences, as in maize, it becomes unnecessary to as- 

 sume the introduction of the intolerance of self-pollination from 

 another group. 



3. Collins leaves in this paper, as well as in an earlier one, 6 

 the impression that the alternative to his hybrid origin hypoth- 

 esis is the theory that maize originated as a mutant from teosinte. 

 The latter idea is quite as chimerical as the former. We can not 

 reasonably hope to find the ancestor of maize in any modern 

 plant ; phylogenetic histories seldom work out in this way. The 

 logical procedure is to look for other plants which may have 

 descended, coordinately with maize, from a common ancestor. In 

 Tripsacum and Euchlcena we find two genera that fill the re- 

 quirements in all known details. 7 



The intolerance of inbreeding in maize is probably the plant's 

 natural evolutionary response to its environment. The maize 

 plant is unique among the grasses in hearing but one pistillate 

 and one staminate inflorescence, or at most only a few inflor- 

 escences of each type, in having these widely separated, and in 

 having been grown in hills for untold centuries. These condi- 

 tions all tend toward extensive cross-pollination, and the data at 

 hand indicate that cross-pollination is the rule. More or less ad- 

 justment to these structural characters and this mode of living 

 would be expected; and the decline in vigor, resulting from in- 



