126 BOTANICAL GAZETTE [august 



and of simultaneous development are especially well revealed 

 in self-fertilization of numerous species that are homomorphic 

 hermaphrodites. Judged by ability of sex organs to function 

 together, both femaleness and maleness of sex organs are seen 

 in such cases to be of various grades of intensity. Such cases 

 reveal that grades of functional or physiological sexuality may 

 be quite independent of morphological sexuality. The striking 

 feature of incompatibiUties, however, is that sex organs which 

 are functionless in some relations are highly functional in certain 

 other relations. For example, it is not complete loss of female- 

 ness, but only a loss in relation to certain degrees or grades of 

 maleness. 



The conditions that exist in Campanula carpatica (Pellew 21) 

 are of special interest in indicating that variations in the relative 

 development of sex organs and physiological incompatibilities may 

 both operate in a single species. Pellew finds that there is a 

 wide range of variations from normal hermaphrodites to females 

 quite as I have described in P. lanceolata; it is also reported that 

 nearly all hermaphrodites are self-sterile (physiological incompati- 

 bility). The "self-sterile" hermaphrodites used in the experiments 

 set seed to cross-pollination, but the extent to which self- and 

 cross-incompatibilities may be operating among hermaphrodites 

 and in crosses of hermaphrodites with females was not determined, 

 and the studies do not reveal whether or not some plants classed 

 as hermaphrodites may be impotent as to femaleness. 



The inheritance of various grades of intersexes in P. lanceolata 

 is a problem under investigation, and a discussion of the researches 

 (Correns, Bartlett, Goldschmidt, Riddle, Pellew, etc.) bear- 

 ing on this question therefore will not be made here. 



It is quite clear that sex differentiation is to be considered 

 as morphological and as physiological. Physiologically the essen- 

 tial and only index of sex in cells is the capacity for their fusion 

 which culminates in the expression of that function by sex cells. 

 It is in decided contrast to that property of asexuahty which is 

 seen in cell division and cell growth. 



Morphological sexuality consists purely and solely of adap- 

 tations to facilitate the bringing into juxtaposition cells that are 



