DOUBLE FLOWEKS. 



469 



DOUBLE FLOWEES. 



By Miss E. E. Saunders, F.L.S., F.E.H.S. 



[Read November 5, 1912; Mr, W. Bateson, F.R.S., in the Chair.] 



The subject of " double " flowers is one of considerable interest to all 

 who, whether from the aesthetic or the commercial point of view, are 

 at pains to consider decorative effect in the garden ; while to the purely 

 scientific botanist, whether morphologist, physiologist, or breeder, the 

 subject presents problems which are still largely unsolved. 



The morphologist is concerned with the nature of the modification 

 which the flower has undergone in the process of becoming double; 

 the physiologist with the causes which call forth this structural 

 change; and the breeder, more especially, with the relation of the double 

 character to the normal — of the sport to the type — in other words, 

 with the question of inheritance. 



As regards the precise physiological causes which lead to the 

 formation of double flowers we still have little exact knowledge. 

 Gardeners in the past have held views as varied as they are often 

 fantastic, and even contradictory, as to the methods to be employed for 

 obtaining or increasing the yield o'f doubles. Thus, e.g. in the case 

 of Stocks the German growers advocate a method of starvation, 

 growing the plants in pots and giving them only sufficient water to 

 keep them alive; on the other hand, a French grower — Ohate — in 

 whose family the cultivation of Stocks had been carried on for more than 

 fifty years, upheld the practice of removing the weaker branches from 

 the plant, and many of the pods from the stronger ones, in order that 

 all the sap might be employed in nourishing those that were left. 

 Some of these traditions, still linger, but for the most part they have 

 no more than an historic interest. So far as I am aware there is no 

 known instance in which we can at will, by any specified method, 

 induce the production of doubles in plants which, when not thus 

 treated, exhibit no tendency to double, and upon this part of the 

 subject I have here nothing further to add. 



As to the morphological causes of doubling, we have the very 

 full account by Professor Goebel of his investigations on this difficult 

 point published in 1886.* By microscopic examination of the earliest 

 stages in the development of the flower he was able to determine the 

 precise nature of the doubling in a large number o'f genera, and the 

 views here expressed as to the nature of the doubling in the types 

 considered are mainly taken from his account. 



It is, however, more especially in regard to the third aspect of the 

 subject, viz. the consideration of doubling from the hereditary stand- 



^ * See " Beitrage zur Kenirtnies gefiillter Bliithen " in Prinnsheim's Jahrhuch, 

 Bd. 17, 1886. 



