108 Self-Incompatibility in Hermaphrodite Plants 
which were not fertilized. It may be, however, that in some of these 
phenospermic achenes embryo abortion occurs as an expression of in- 
compatibility after fertilization. This appears also to be the case for 
feebly self-fertile plants of Eschscholtzia californica as noted above. 
The ability of such plants to produce abundant seed to compatible cross- 
pollinations at the same time that phenospermic seeds are produced 
among heads selfed indicates that any embryo abortion which may occur 
is associated with incompatibilities rather than with inability of parent to 
nourish young embryos. It is to be recognized however that in chicory 
the development of the head as a whole may in large measure depend 
on the number of ovules fertilized properly, and that the development 
of the individual seeds in a head may thus be influenced by local relations. 
If such is the case, the effects would be most liable to appear in plants 
partially or feebly self-compatible. 
Considerable cytological investigation has been directed to the study 
of these conditions in chicory, but at’ the moment of writing the observa- 
tions are not conclusive as to the extent to which true embryo abortion 
may occur. The results, however, indicate that in plants fully self-incom- 
patible there is complete failure in fertilization due to the poor growth 
of pollen tubes. In plants feebly self-fertile there appear to be various 
stages at which the processes of fertilization may fail. 
Il. The heredity of self-compatibility in self-fertilized lines of descent 
in the variety red-leaved Treviso of Cichorium Intybus. 
The immediate parents of this generation were highly self-fertile 
plants which had descended from three generations of ancestry known 
to have been self-sterile at least during the early part of their period of 
bloom. The race had been kept in culture by rather close inbreeding. 
This generation therefore afforded material for the study of the heredity 
of self-fertility after it has arisen sporadically in an inbred variety. 
The number of plants grown in the J,, and also the J,, was so large 
that it was impossible to test all of these by controlled hand pollination 
(described 1916, p. 362) as was done in previous studies with this species. 
The plants were tested by autonomous self-pollination. Flower heads | 
were allowed to open and close under a bag. Such heads were appro- 
priately tagged and allowed to continue development in the open. AS — 
a rule flower heads of chicory are open but a few hours during the fore- 
noon ; by midday they are closed never to open again, and the next day 
the corollas and styles fall. The entire afternoon can be devoted to 
