Oct., 1923] 
STOUT — STUDIES OF LYTHRUM SALICARIA 
449 
exhibited in selfing, suggests that wide variations may likewise be expected 
for crossings even for those that are legitimate. 
5. One noticeable case of end-bioom self-compatibility was found. This 
was in a mid-styled plant and involved only fertilizations from pollen of 
the set of long stamens. 
6. The physiological relations of the sex organs in plants of this tri- 
morphic species exhibit quite the same range of variations as are seen in 
many homomorphic species. 
Conclusion 
For the species Lythrum Salicaria 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 the sexual relations of the three forms of Lythrum Salicaria . Jour. 
Linn. Soc. Bot. 8 : 169-196. 
-, 1877. The different forms of flowers on plants of the same species. 
