270 University of California Pvhlications in Agricultural Sciences [Vol. 2 



The style is bifid with the sti^matic surface on the adjacent faces 

 of the lobes. With the beginning: of anthesis the style elongates, 

 pushing the upper end out from the stamen tube and sweeping the 

 pollen out with it on its outer surface. The stigmatic lobes then 

 separate and assume a position at right angles to the style. The pollen 

 at this stage is below the receptive surface of the stigma, which is, 

 however, exposed to insects, the means by which cross-pollination is 

 effected. Later the stigma lobes curl into a short spiral which brings 

 the receptive surface of the stigma in contact with its own pollen or 

 that of an adjacent floret of the same head. Under natural conditions 

 Crepis is often cross-pollinated by insects, and this preserves a 

 heterozygosity of the germinal material. A similarity of the effects 

 of continued inbreeding in Crepis to the effects of inbreeding in maize 

 has been noted (Collins, 1920). It was shown that inbreeding caused 

 a reduction in the size of the plants and increased the length of the 

 vegetative period. Other data are now available which show in 

 another way the general heterozygosity of Cre-pis capillaris as it 

 occurs in a wild state. Thus the seed collected from a few wild plants 

 near Eureka, California, has been the source of the following races : 

 viridis, scalaris-e28, pallid, and revolute (leaf form variations) ; of 

 three types of partial albinos (chlorophyll development) ; and of the 

 variations, dwarf III and fasciation (the plant as a whole). From 

 the Berkeley wild plants we have obtained plants with smooth ribs 

 and the leaf form H6 ; from England, the leaf form simplex -Z9 ; from 

 France, dwarf II, spreading, chlorina, and tubular flowers. Palea 

 probabl}' came from the Danish material. As mentioned in another 

 section, bald has appeared independently in the cultures from six 

 different geographical regions. The Eureka stock has produced the 

 greater number of new races. This is not taken to mean that it is 

 necessarily more heterozygous but that many more plants from this 

 source have been under observation. We have presented here an 

 instance of a remarkable germinal diversity in locally developed 

 strains of a single species. Although many of the characters appeared 

 only after hybridization between local races or stocks, the evidence 

 does not, except in a few cases, show these characters to be due to 

 complementary factors. The appearance of bald from such widely 

 separated localities as Chile and Sweden and from other less widely 

 separated localities is of particular interest, for it shows that either a 

 certain locus of the germinal material mutates more readily than 

 others or that all these local races have originated from a single stock 



