Oct., .„. ] STOUT — STUDIES OF LYTHRUM SALICARIA 449 



exhibited in selfing, suggests that wide variations may likewise be expected 

 rrna-fc^ t -ings even for those that are legitimate. 



crossec ie noticeable case of end-bloom self-compatibility was found. This 



the hi' ..mid-styled plant and involved only fertilizations from pollen of 



Whetht .ilong stamens. 



last par- physiological relations of the sex organs in plants of this tri- 



jpecies exhibit quite the same range of variations as are seen in 



ui'du. } amorphic species. 



Conclusion 



For the species Lythrum SaUcaria the evidence of wide variation in the 

 degree of self-incompatibility is definite. The physiological differentiations 

 of the sex organs are incompletely correlated with the apparent structural 

 adaptations for cross-pollination; they are not fixed, constant, and fully 

 achieved either in expression or in heredity, but are fluctuating and inter- 

 grading. They still present opportunity for further selection either toward 

 greater or toward less restriction of fertilization. 



The persistence of self-compatibility in various degrees of expression, 

 and the apparent difference in respect to self-compatibility seen among the 

 various forms, present strong evidence that self-compatibility was the 

 antecedent condition in the species out of which the present complex of sex 

 relations is still evolving, just as the sets of styles and stamens of different 

 lengths have been developed out of an original homomorphic species. 



New York Botanical Garden 



LITERATURE CITED 

 Darwin, C. 1865. On thejsexual relations of the three forms of Lythrum SaUcaria. Jour. 



Linn. Soc. Bot. 8 : 169-196. 

 , 1877. The different forms of flowers on plants of the same species. 



