208 Plant Genetics 



but it would not be appropriate to enter into the 

 theoretical complications any further. In this con- 

 nection, however, we may recall the work of CIESIELSKY 

 (see page 195), in which it is claimed that staleness 

 of pollen affects sex. Staleness probably means an 

 unusual amount of oxidation and would be a typical 

 instance of " unusual physiological conditions." One 

 might predict that staling of pollen might be found to 

 affect other plant characters as well as sex. This sug- 

 gests a new field of investigation. The male gamete 

 of angiosperms, however, is pretty well insulated within 

 the pollen coat. If work of this kind is to be done, 

 the algae and fungi would furnish much more favorable 

 material (see page 130). 



These are two theoretical pictures in which both 

 chromosomes and physiological conditions may play 

 their roles. The latter is more complex, but at the same 

 time more exact and more suggestive of further investi- 

 gation. Both are highly theoretical and should not be 

 confused for a moment with any of the actual known 

 facts of inheritance. At best either one of them may 

 help to unify the situation that has been discussed, and 

 unless some such scheme is constructed it will be found 

 difficult to keep one's bearings among conflicting theories 

 based upon apparently conflicting facts. 



1. DONCASTER, L., The determination of sex. Cambridge Univ. 



Press. 1914. 



2. MACDOUGAL, D. T., see Heredity and eugenics (CASTLE, COUL- 

 TER, DAVENPORT, EAST, TOWER). Chicago. 1912 (p. 205). 



3. WILSON, E. B., Heredity and microscopical research. Science 

 N.S. 37:814-826. 1913. 



