NOTE ON THE EVOLUTION OF THE DOUBLE 

 STOCK (MATTHIOLA INC AN A). 



By EDITH R. SAUNDERS, 



Fellow of Newnham College, Cambridge. 



(With Three text-figures.) 



The question whether the fully double Stock, as we know it to-day, 

 arose in the first instance by a single considerable mutation producing 

 the form with which every flower lover is familiar, must have arisen in 

 the minds of many horticulturists since the plant became a favourite in 

 our gardens. So far as I am aware no statement exists as to when, where 

 or by whom the double form was first observed. The earliest reference 

 known to me, as I have stated elsewhere\ is that by Dodoens^ in 1568. 

 In this account as in the later illustration by de I'Obel and Pena* (1576) 

 it is a full double which is depicted, a double, that is, destitute of any 

 semblance of either stamens or carpels. In view of this testimony and 

 of the further facts (1) that all double Stock strains now in cultivation 

 are of this fully double type, (2) that we know that in the case of certain 

 other genera having different grades of doubles (Wallflower, Lobelia) the 

 appearance of the full double preceded — in the former case probably by 

 some centuries — that of the semi-double, (3) that in a full double of such 

 recent origin as Arahis albida we have no knowledge of any intermediate 

 stage in the doubling process, we may safely accept the evidence for the 

 mutation having been accomplished in the Stock by a single step as 

 amounting to proof. Nevertheless we meet with some records in the 

 literature dealing with Matthiola which might be construed as conflicting 

 with this view, and which in any case call for some further explanation. 

 I have been unable until now to come to any definite conclusion in regard 

 to this counter-evidence, but certain specimens noticed of late in my own 

 cultures appear to me to provide the solution. I have therefore thought 



1 "The Double Stock, its History and Behaviour," Journal Roy. Hort. Soc. Vol. xl. 

 Part III. 1915. 



•^ Florum et coronarianivi 



* Stirpium adversaria nova. 



