1923] Bau: Morphological Characters in Crepis Capillaris 219 



partly in the greenhouse and partly in the field and the results have 

 been found so consistent that the data have been combined. The 

 investigations herein reported were started in the fall of 1920 and 

 were carried on by the writer until July, 1922, but a great deal of 

 preliminary purification of material had been done before the material 

 was turned over to me. 



The work was undertaken at the suggestion of Professor E. B. 

 Babcock, head of the Division of Genetics, University of California, 

 to whom my best thanks are due. My thanks are also due to Dr. R. E, 

 Clausen and Mr. J. L. Collins, of the Division of Genetics, for espe- 

 cially valuable help and suggestions during the progress of the in- 

 vestigations. 



MATERIAL AND METHODS 



The detailed work has been done on three inbred families. The 

 achenes were always germinated in seed pans in which the soil had 

 been sterilized, or which had been filled with soil near which no Crepis 

 plants had been grown Mathin the last few years. The achenes were 

 lightly covered with soil and watered. The germination was fairly 

 rapid and the seedlings were ready for transplantation in about four 

 weeks from the date of sowing. They were transferred either to small 

 cardboard boxes about two inches square and planted out in the field 

 or to 4-inch or 6-inch pots directly. The size of the pot had very 

 little influence on the early development of the plant although, so 

 far as general vigor was concerned, the plants in the 6-inch pots gave 

 better results. 



In measuring the length of the leaves and determining their lobe 

 number, the plants were allowed to develop as far as possible in the 

 rosette stage and data were secured before the central axis appeared 

 with the formation of the cauline leaves. The length of the leaf was 

 measured on a centimeter scale and the number of lobes counted on 

 one side of the leaf, usually the left side. Every lobe which was sup- 

 plied with a distinct vein was given a unit rank and in these calcula- 

 tions all scurs at the base of the leaf and the secondary lobes attached 

 to the main ones were not considered. Five leaves were indiscrimin- 

 ately chosen and counts made upon them. 



The capitula were measured on the centimeter scale when they 

 were fully open. Flower heads in Crepis open centripetally, and a 



