394 



A, B. STOUT 



Standing of morphogenetic differentiation involved in sexuality, but of 

 which we have at the present time only a superficial knowledge. 



When does physiological incompatibility begin to develop? Is it 

 a steady and progressive development through the whole diploid 

 association of the two parental cell elements involved, or is it achieved 

 suddenly at some particular point in ontogeny? Also, when does the 

 sexual condition as distinct from the asexual condition actually arise? 



Does incompatibility arise because of sex? Are the two the same? 

 It would seem most definitely that they are not and that incompati- 

 bilities are not merely due to sexuality. But even if independent, 

 where incompatibilities do arise, where, how, and to what extent are 

 they correlated with sex and is the development of the two ever 

 parallel? To what extent are the physiological interrelations of 

 sexuality and incompatibility dependent on such mechanical or 

 chemical interactions as are involved in reduction and sporogenesis? 



Are the differences of intra-varietal physiological compatibility 

 and incompatibility (both self and cross) indicative of differences in 

 sexuality as such? Are some of the organs of either sex (microgameto- 

 phytes and macrogametophytes with their respective gametes) 

 sometimes more sexual or of greater sex vigor than are others? 



To what degree are the incompatibilities, and compatibilities as 

 well, determined by nutritive relations that are to be considered as 

 vegetative functions? Is sexuality in its origin and in its phenomena 

 of cell fusions, as some have held, to be considered in reality as a 

 phase of vegetative function? To what extent are the sexual incom- 

 patibilities related to phenomena of serum incompatibilities and to 

 immunity and what are the fundamental reactions involved in the 

 development and operation of these? 



These are among the fundamental questions that naturally arise 

 in connection with such sporadic behavior of functional sex vigor as is 

 seen in chicory in which self-fertile plants of varying degrees of fertility 

 arise among a progeny even after three generations of parentage 

 known to be self-sterile. 



New York Botanical Garden 



BIBLIOGRAPHY 



Compton, R. H. 1912. Preliminary Note on the Inheritance of Sterility in Reseda 



odorata. Proc. Cambridge Phil. Soc. 17: Pt. I. 

 1913. Phenomena and Problems of Self-sterility. NewPhytologist 7: 197-206. 



