F. Kebble 165 



massive head and bear large petals the outer margins of which are 

 not notched {stellata type) but fimbriated. 



There is however no necessary connection between gigantism and 

 the sinensis type of petals: indeed Messrs Sutton's remarkable collection 

 of Primulas contains at the present time numerous giants which bear 

 flowers of the stellata type. 



Further, although the giants in general cultivation have the sinensis 

 style of inflorescence, there is no essential connection between gigantism 

 and that type of inflorescence. For example, the giant (Giant White 

 Queen Star), the origin of which is about to be described, is charac- 

 terised by the possession of a typically stellata, habit of inflorescence 

 {cf. Plate XI, fig. 2). 



III. The Mode of Origin of Giant White Queen Star. 



Among the Primulas which have been grown at University College, 

 Reading, during the last ten years is a well-known variety, White 

 Queen Star (Plate XI, fig. 1). This variety — a reddish stemmed, palm- 

 leaved strain with white flowers of stellata form and habit — was raised 

 from seed presented by Messrs Sutton in 1903. 



Plants of the first generation of White Queen Star raised from 

 these seeds were self-fertilized in 1904 and yielded an F^ generation 

 which, so far as the records show, presented no departure from the 

 normal form. 



Of the plants of the F^ generation raised from seed obtained by 

 self-fertilizing Fj plants, some bore an occasional 6-petalled flower 

 among the other normal 5-petalled flowers. Fluctuations of this kind 

 are of course common in P. sinensis, and also in many other cultivated 

 plants. They appear suddenly in one generation, may be lost sight 

 of in the next ; and their advent and disappearance are generally 

 ignored. 



Notwithstanding the strength of the evidence that such fluctuating 

 variations arise and fade away without leaving recognizable after- 

 effects in the descendants, experiments were undertaken with the 

 object of testing the degree of permanence of the variation which 

 results in the production of flowers with supernumerary petals. 



As may be seen from the results of the experiment summarised in 

 Table I the attempt to produce a race characterised by the possession 

 of flowers with more than the normal number of petals was not 

 successful. Inasmuch however as the experiment of breeding from 



