INTERSEXES IN PLANTAGO LANCEOLATA 



A. B. Stout 



(with plates xji, xiii) 



Through the resent researches of Goldschmidt (ii, 12, 13), 

 Banta (i), Whitman, Riddle, and their associates (see especially 

 summaries by Riddle 22, 23), and Lillie (17, 18), the facts of 

 intersexualism have acquired a significance which must be con- 

 sidered by any theory of sexuality and sex determination. These 

 new studies show that in widely separated groups of animals which 

 are usually dioecious various grades and degrees of maleness and 

 femaleness in a single individual are common. Judged as entire 

 individuals, such "intersexes'' or "sex intergrades" may be pre- 

 dominately male or female, or there may be various grades in the 

 relative development of maleness and femaleness, giving in some 

 cases at least functional hermaphrodites. Along with these there 

 may be individuals that are only male or female. An individual 

 sex organ may start development as of one sex and change to the 

 other, or there may be a decidedly simultaneous development of 

 male and female sex organs, as in the fully functional hermaph- 

 rodite. The more remote secondary sex characters also exhibit 

 characteristics of maleness, femaleness, or various grades of 

 modifications that are intermediate. 



Such development of intersexuality in forms usually consid- 

 ered as dioecious is evidence that even in dioecious forms sex is 

 not necessarily determined at fertilization, and that sex is not 

 alternative and irreversible for an individual or even for a sex 

 organ. The data are particularly suggestive of the probability 

 that sex differentiation in dioecious forms and in hermaphrodite 

 forms is essentially the same process, and thus that sex determi- 

 nation is on the same fundamental basis in both plants (which 

 are prevailingly hermaphrodite) and animals (which are prevail- 

 ingly dioecious). 



In plants the most intimate association of the two sporophytic 

 sex organs is seen in the so-called perfect flowers. The opposite 

 109] - [Botanical Gazette, voL 68 



