AMERICAN 
JOURNAL OF BOTANY 
FERTILITY IN CICHORIUM INTYBUS: THE SPORADIC 
OCCURRENCE OF SELF-FERTILE PLANTS AMONG 
THE PROGENY OF SELF-STERILE PLANTS 
The writer (1916) has already presented the evidence that the 
very prevalent self-sterility (and cross-sterility as well) in chicory can 
be ascribed to a physiological incompatibility operating between sex 
organs or sex cells that are fully formed, anatomically perfect, poten- 
tially functional and of simultaneous development. It was noted that 
this type of sexual sterility is sharply to be distinguished from sterility 
due to anatomical incompatibility (more or less purely structural dif- 
ferences and adaptations such as hercogamy), impotence (failure to 
produce gametes) or embryo abortion (death of egg after fertilization 
or death of young embryo). I also at that time discussed and sum- 
marized the literature bearing on such phenomena. 
From my studies made in 1912 and 1913, it appears (Stout 1916, 
p. 365-366) that self-sterility is the rule in chicory. Three plants (des- 
ignated A, By and C) of wild stock were found to be self-sterile, as 
were 52 plants grown from the open fertilized seed of these plants, 
and all plants tested of ten cultivated varieties were self-sterile. In 
one variety (Barbe de Capucin), 29 plants of one planting and 5 of 
another were tested, and of other varieties about five plants of each 
were tested. The total of about 135 plants from these various sources 
were self-sterile. 
However, in the pedigreed cultures grown in 1913, a few plants 
exhibiting varying degrees of self-fertility appeared quite sporadically 
among the Fi progeny of various crosses between self-sterile plants. 
Of the 75 plants derived by crossing plant A with plant E22 (of the 
variety Barbe de Capucin), only eight were self-fertile. Of 21 plants, 
Vol, 4 
July, 191 7 
No. 7 
A, B. Stout 
[The Journal for June (4: 315-374) was issued June 29, 1917] 
375 
