Volume IV APRIL, 1915 No. 4 



NOTE ON THE INHERITANCE OF HETEROSTYLISM 

 IN PRIMULA ACAULIS J ACQ. 



By R. p. GREGORY, M.A. 



Fellow of St John's College, Gamhridge; University Lecturer in .^ 



Botany. ,jj 



The experiments with the wild Priimose, which it is the purpose of aAKUK"-^* 

 this note to record, were begun by Mr Bateson and the writer con- 

 currently with our exj)eriments on Primula sinensis^. The results 

 obtained in the two species are exactly similar ; the inheritance of the 

 characters of short and long style is of a simple Mendelian type, the 

 short style being dominant, the long style recessive. 



The two forms of the wild Primrose are about equally numerous in 

 nature-. Among the wild plants used for experiment were nine short- 

 styled plants, all of which proved to be heterozygous. Darwin' found 

 the " illegitimate " mating short-style x short-style to be relatively even 

 less fertile in the Primrose than it is in P. sinensis; my experiments 

 have given a similar result, and from numerous matings of this kind 

 only five families have been obtained ■*. Two of these families were the 

 offspring of wild plants ; they consisted of 13 short-styled, 4 long- 

 styled plants. Of these 13 short-styled plants, only two produced any 

 offspring ; one of them shewed itself to be heterozygous, giving 1 1 short- 



' Bateson and Gregory, Roy. Soc. Proc, B. Vol. Lxxvi. p. 581, 1905 ; Gregory, Journal 

 of Genetics, Vol. i. p. 73, 1911. 



2 Darwin, Forms of Flowers, p. 34. I have counted the two forms in several localities 

 where the plant grows wild, without finding any significant departure from equality of 

 numbers. 



» L.C., p. 37. 



* The plants used for experiment were grown out-of-doors, in pots covered with muslin 

 bags, ao that flowers which had been operated upon were exposed to the weather at a time 

 of year when frosts are common. As a consequence a great number of the experiments 

 were unsuccessful, and the whole of the crosses made in 1905, and again those made in 

 1907, were lost. 



Journ. of Gen. iv 20 



