484 University of California Puhlications in Botany [Vol.5 



It was possible as in previous instances to segregate the plants into 

 definite flower color classes. In order to make this segregation as 

 accurate and free from bias as possible a special method of classifica- 

 tion was adopted. At the height of the blooming season, single typical 

 flowers were collected from each plant of a population and placed in 

 vials correspondingly numbered. These specimens were then taken 

 into the laboratory, where they could be classified under optimum light 

 conditions. The specimens so collected could then be shifted around 

 into their phenotypic classes and properly compared with each other 

 and with the parent colors. The color classification thus obtained 

 M^as individually recorded, and later the population was checked over 

 in the field to insure correction of any errors of classification. The 

 surprising feature of this population was a sharp, three-class segre- 

 gation into red, pink, and light pink ; the reds the shade of macro- 

 phylla, the light pinks almost exactly that of angustifolia, and the 

 pinks intermediate between the two. Within the classes there ap- 

 peared to be no significant differences in depth of shade. Two plants 

 bore no flowers. The ratio obtained was 15 red : 23 pink : 10 light 

 pink. 



IGFoHoPiT was likewise a sowing of the seed of one of the original 

 F^ plants, in this instance of IOF1H2P17. As respects habit, height, 

 and leaf shape, there was a strict resemblance throughout of this 

 population to the one described above. Flower color was studied in 

 the same manner and with substantially the same results. However, 

 in this population there was a shading off from pink to light pink, 

 such that it was impossible to draw a sharp line between these two 

 classes as was done in the previous population. The shading off was 

 abrupt, but there were, nevertheless, a few plants on the border line. 

 The observed ratio was 16 red : 34 pink and light pink. 



In 1917 six F3 populations, each containing approximately 100 

 plants, were grown in order to make further studies of the inheritance 

 of leaf shape. It was impossible, however, to study these plants as 

 thoroughly as might have been desired on account of conditons ob- 

 taining during 1917. However, specimens of leaves from each plant 

 were pressed and preserved and these were studied and classified in 

 the summer of 1919. A brief account of each population follows : 



I7F3H2P17P6 was a sowing from IGF.HoPi-Pe, a stenophylla 

 selection. With respect to leaf base characters the segregation was 

 roughly but rather obviously into two types, a long petioled steno- 

 phylla class approximating type 1 in appearance, and an auriculata 



