204 Mendelian Inheritance in Bryonia dioica 



(b) Seedlings raised from seed obtained from Erfurt, N. Germany. 



(c) Plants from tubers sent from an independent source near 

 Erfurt (exact locality unknown). The plants from sources (6) and (c) 

 are identical and may be treated as belonging to one group. 



These two lots of plants j(u) and (6) + (c)j differed from one 

 another in respect to a number of characters relating to general habit, 

 shape of leaf and structure of flower and fruit. 



The differences being constant and equally well-marked in all plants 

 of the same " variety," individual plants were " selfed " and " crossed " 

 in order to determine the genetical ])ehaviiiur of these distinguishing 

 characters. 



It was found that plants " bi-ed true" to type, and that the 

 characters investigated — while showing fluctuation about a mean — are 

 not appreciably affected by cultural treatment. 



There can be no doubt, therefore, that two distinct varieties or 

 petites especes of Bryony are concerned and that plants belonging to 

 either group may be readily distinguished one from the other. 



For the sake of brevity these two varieties will be known through- 

 out this paper as B (native seedlings, (a) in category on p. 203) and G 

 (Uerman seedlings or tubers, (b) and (c) in category on p. 204). 



The characters selected for investigation as being most susceptible 

 of measurement were : 



A. Bloom on the berry. 



B. Number of stigma-bianches and placentae in the ovary {i.e. 

 nuiiilier of carpels). 



C. Number of vascular bundles in the stems. 



/). Habit and leaf-shape. 



It is fully realized that the number of plants available is not 

 suflicient to give satisfactory ratio numbers, especially in cases such 

 as number of carpels (see below). 



It is nevertheless believed that the data are sufficient to establish 

 the general mode of inheritance and to show clearly : 



(a) That within the limits of a so-called "species" a number of 

 varieties occur differing from one another in characters that are 

 inherited according to Mendelian rules. 



{b) That it is therefore possible to produce new combinations of 

 such characters artificially. 



