A. B. Stout 121 



Salicaria) and mid-season self-fertility (in Brassica pekinensis) but 

 from the evidence at h'and these seem to be characteristic of certain 

 individuals rather than a condition regularly present in the species. 

 Such partial variations may be regarded as reversion to the more 

 primitive condition. They exist along with other wide variations in 

 the degree to which self-compatibility operates. 



Not only is there variation in the number of sex organs that function 

 together, but there appears to be considerable variation as to the stage 

 to which processes of fertilization proceed, and also even in the vigour 

 of the seed from fertilizations that are successful. Observations by many 

 investigators confirm the fact that in some cases the pollen tubes make 

 such feeble growth that fusion of gametes is not possible (see especially 

 the recent account by East and Park, 1918), In the case of feebly 

 self-fertile plants (chicory, California poppy, and perhaps the apple, 

 show this very well) many poorly developed seeds stand as intermediates 

 between the few good seeds and the mere rudiments, and suggest that 

 some embryo abortion occurring in plants showing feeble self-compati- 

 bility may be due to certain grades of incompatibility. 



As reported above in chicory, occasional plants and certain lines 

 appear which exhibit decided degeneracy. One such family of chicory 

 has been studied in detail. It showed grades of vegetative degeneracy, 

 viability of seeds containing embryos was low, many plants were weak, 

 small and short lived and many of those that lived were entirely 

 impotent in respect to the development of stamens and pistils. Such 

 conditions certainly suggest that the poor development of offspring may 

 in such cases be an expression of compatibilities between the sex 

 elements and may thus closely parallel the conditions of poor vegetative 

 and sex vigour observed in certain, though of course not all, hybrids. 

 The condition in this one family of chicory is quite like that reported 

 by Darwin (1869, 1877) for the offspring of illegitimate crosses in the 

 trimorphic species Lythrum Salicaria. Still it is to be recognized that 

 we have no proof that degenerate plants or strains are more frequent 

 in species which show self-incompatibility than in those that do not. 



As reported above the heredity of self-compatibility and self-incom- 

 patibility has been specially studied in an inbred variety of chicory, and 

 this problem had previously been studied (1918 a) in the progeny of 

 inter- varietal crosses. The sporadically occurring self-compatible plants 

 were made the beginning of selfed lines of descent, which in certain 

 lines have been continued for three generations. The results obtained 

 during the seven years, during which the self- fertility of over 2,000 plants 



