220 Mendelian Inheritance in Bryonia dioica 



The geographical distribution of these two varieties of Bryony may 

 be of interest in connection with the history of the species as a member 

 of the British Flora. 



All tho British specimens examined by us resemble tyj^e B as 

 described in this paper, and this form has also been noticed by us in 

 South Tyrol. 



The plants of vaiiety G were obtained partly from seed purchased 

 from an Erfurt firm and partly from tubers sent from N. Germany 

 (exact locality unknown), and the plants from these two sources are 

 identical in every respect. 



The fact that the two strains breed true to type and give so many 

 hybrid types on crossing suggests that their geogi-aphical distribution 

 may be discontinuous, but this point has been imperfectly studied and 

 awaits further investigation. 



This part of the enquiry has of necessity been abandoned tem- 

 porarily owing to the war, and it is hof)ed that the publication of the 

 paper in its present form may lead to the collection of further data 

 bearing on geographical distribution from readers who may be 

 interested in the facts described. 



In a paper published in 190.5 entitled " Parthenogenesis und 

 Variabilitat der Bryonia dioica " Bitter discusses the variability in size 

 and shape of leaves, as also in size, colour and structure of flowers 

 (corolla of % flower), observable in plants of Bryonia dioica from various 

 localities in Mtinster, under observation in cormection with an in- 

 vestigation into the occurrence of parthen(jgenesis in the species. 



He also remarks on the absence from the Floras of varietal forms 

 distinguished on such characters. 



Bitter describes and figures leaves and flowers from his cultures, the 

 former being of interest in connection with the facts described in this 

 paper, since they demonstrate the existence of our B and G varieties in 

 Mlinster and also that of at least one of the more distinct hybrid leaf- 

 types bred by us. 



This author's observations on vai'iability in size, shape and colour of 

 flowers coincide with our own in many respects, and it seems likely that 

 the plants he describes would have fitted easily into our scheme of 

 inheritance. 



Bitter's observations were mainly concerned with parthenogenesis, 

 and he concludes tentatively that variability in B. dioica is dii-ectly 



