116 Self-Incompatibility in Hermaphrodite Plants 
fertility. In the J,, Series 12-11 was more self-fertile both as to pro- 
portion of plants and range of self-fertilities. In the J,, considering 
each family as a whole, there was no difference in the proportion of 
plants, but the ranges were higher for one series of the family 72-—11-— 
Some irregularities are apparent in which the behaviour of offspring 
is not directly to be gauged by the degree of self-fertility of a parent. 
In the J, of family 10-8 one series (10-8-173) gave a ratio of 2 self- 
sterile to 1 self-fertile while in the other series this ratio was reversed ; 
the grades of self-fertility for the three immediate parents were almost 
identical and they all had the same ancestry preceding. In the J, of 
the family 12-11-, the two series were obtained from parents of almost 
identical self-fertility ; one of these (12~11-49) was of decidedly feeble 
self-fertility in comparison with the other (12-11-16). 
IV. Vegetative vigour and impotence in self-fertilized lines in the 
variety red-leaved Treviso of Cichorium Intybus. 
The various grades of seed development and embryo abortion in 
plants feebly self-compatible suggest strongly that individuals of 
various grades of vegetative growth may arise through various grades 
of compatibility in the fertilizations. The physiological basis for 
degeneracy 1 in individuals or races may thus be sought, in part at least, 
in the comparative weak compatibility of the elements which unite in 
fertilization. That this is the case is also suggested by the evidence 
that inbreeding and continued self-fertilization is not of itself injurious. 
The self-fertilized lines of descent. in this variety of chicory were 
derived from a race that was kept in culture for three years by cross- 
fertilization of rather closely related plants. Undoubtedly the variety 
had previously been maintained largely by crossing, and it is a salad ° 
chicory that has been developed and maintained by selection for 
‘vigorous vegetative growth. Under such treatment there has been a 
constant selection of the offspring of highly compatible fertilizations and 
an elimination of weak individuals which in my culture have been given 
a chance for their complete development. 
In the cross-fertilized stock of the first three years of culture there 
_ were occasional plants that exhibited signs of degeneracy. The leaves 
and branches were few and poorly developed, flower heads did not open 
fully, corollas were crumpled, and many anthers were dark coloured, 
contained few well-developed pollen grains and often did not dehisce. 
Such plants produced few seed to open cross-pollination. During the 
