1923] Eau: Morphological Characters in Crepis Capillaris 235 



flattened on two sides assuming the shape of an oval as opposed to 

 the normal round shape and at times, owing to a shortening of the 

 pedicels, two or three flowers appear to be joined together. All these 

 malformations have been noted in one or another of the cultures, and 

 emphasize strongly the effects of inbreeding in bringing to light 

 undesirable recessive characters which are disadvantageous to the 

 growth of the individual plant. 



The outcome of this portion of the work has given results in no way 

 contradictory to the conclusions arrived at by other investigators who 

 have relied upon multiple factors as an explanation of inheritance of 

 quantitative characters. As the experiment has not been carried to 

 the F3 stage, it is not possible to state whether this material will yield 

 results entirely consistent with the requirements (East, 1916) of the 

 multiple factor hypothesis. But as far as the results go, they are in 

 agreement with the explanation suggested that inheritance of the 

 number of lobes in Crepis capillaris is a Mendelizing quantitative 

 character and that it is controlled by many factors which affect 

 occurrence of lobes, depth of the incisions, number of lobes, and shape 

 of the lobes. 



It may be here noted, in passing, that in a work of this nature a 

 certain amount of discretion is necessary in determining the class to 

 which a given individual belongs. Classification of the shape of a 

 leaf and the exact number of its lobes are, to a certain extent, decided 

 by the investigator, who can handle them quickly as he gains practice. 

 Moreover, the exact times when the measurements are to be taken 

 are more or less fixed by the investigator himself, who should try to 

 secure as uniform material as possible in the several generations. 

 East (1921) has raised a similar point in his work as regards the 

 personality of the investigator. He says, ' ' I believe that in such work 

 as this, the investigator who lives with his plants in the field, who 

 uses all the quantitative data at his command, but w^ho, nevertheless, 

 brings to his aid all the somewhat intangible facts that intimate experi- 

 ence gives him is able to come to a better realization of the truth than 

 one who works on cold data obtained by others. ' ' 



2. Size of capitulum is a character which is controlled by genetic 

 factors, and it is fairly constant for a given family. It is practically 

 independent of the size of the plant and it cannot fall below a certain 

 minimum. It is also independent of the number of capitula on the 

 entire plant or the number of florets per flower head. It is similarly 

 uninfluenced by the shape of the plant. The tall, erect, vertical type 

 of plants, and the bushy spreading type of plants (pi. 43) have given 



