UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



AGRICULTURAL SCIENCES 



Vol. 2, No. 9, pp. 249-296, plates 45-52 December 31, 1924 



INHERITANCE IN v . . .., 



CREPIS CAPILLARIS (L.) WALLR. III.^ 



NINETEEN MORPHOLOGICAL AND THREE 

 PHYSIOLOGICAL CHARACTERS^ 



BY 



J. L. COLLINS 



INTRODUCTION 



For several years variations in Crepis capillaris have been studied 

 genetically. The study was commenced^ in the hope of being able 

 to determine whether the extensions of the Mendelian theory of 

 heredity which were based on breeding data from Drosophila melano- 

 gaster would hold for higher plants. For this purpose it was necessary 

 to know the mode of inheritance of a number of characters. This 

 paper is concerned with the description and mode of inheritance of 

 a number of variations found in Crepis capillaris (L.) Wallr. 



It is evident that the material chosen for such a purpose should 

 show variation of a hereditary nature and should also contain a low 

 number of chromosomes. Crepis capillaris seemed to fulfil these 

 requirements, for its chromosome number, 3 pairs, is the lowest 

 reported for the higher plants, and the species is known as a variable 

 one. 



Linkage has been demonstrated in a number of plants and in some 

 of the higher animals. Unfortunately, the chromosome number in 

 those species in which linkage has been observed is relatively high, 

 and in no case is the number of groups of linked genes equal to the 

 haploid number of the chromosomes. 



1 This is a report on a part of a project supported by appropriations from the 

 Adams Fund. 



2 Studies commenced by Professor E. B. Babcoek in 1915 and carried on by 

 the writer under his direction since 1918; published as nos. 6 and 7 of vol. 2 in the 

 present series. 



