DOUBLE SEEDING PETUNIAS 



Crossing and Selection Result in Production from Single and Imperfect Double 



Types of Four Strains That Are Double and Produce Seed — Methods of 



Operation — Curious Variations Observed^ 



Mrs. Myrtle Shepherd Francis, Ventura, Cal. 



BEFORE presenting the subject 

 of my double petunia that 

 reproduces itself, I want to 

 state that I claim no scientific 

 attainments, that while the scientific 

 aspect of the work has been of deep 

 interest to me my chief aim has been to 

 produce the finest strains of double 

 petiuiias to be had in the market and to 

 make those strains reproduce them- 

 selves. Competent authority assures 

 me that my work has been succcssfiil. 



Data regarding the crossing of both 

 single and double petunias is exceed- 

 ingly difileult to obtain as most of it is 

 scattered about in horticultural reports 

 and magazines. 



The first single petunia was found by 

 Commerson in Argentina, on the banks 

 of La Plata River, and sent by him to 

 Jussieu, who named it Petunia nycta- 

 gina flora, introducing it into France in 

 1823. This i^lant had an upright habit 

 with thick sticky leaves and long- 

 tubed fragrant white flowers. The 

 second species was sent by Tweedie 

 from Buenos Ayres to the Glasgow 

 Botanical Gardens in 1831. This plant 

 had a decumbent habit, small violet 

 purple flowers and short tube and was 

 named Petunia violacea. From these 

 two species all varieties of petunias have 

 been bred. They have been freely 

 crossed with each other; hence the 

 garden varieties now go under the 

 general name of Petunia hyhrida Hort. 



While the nyctaginaflora type is 

 quite common, the true violacea form 

 is seldom seen, proving that the nycta- 

 ginflora s])ecies was the dominant factor 

 in the early crosses. Even today most 

 varieties revert to that form when left 

 to themselves. 



For convenience sake I shall loosely 

 divide the single varieties now under 

 various names into two classes: those 

 with upright habit, long-tubed flowers 

 with small reproductive organs, slender 

 style and filament adherent low down 

 in the corolla tube and wide range of 

 colors with satiny texture, as hybridas, 

 representing P. nyctaginaflora; and the 

 varieties with the deciunbent habit, 

 large leaves, flowers with short tube, 

 large reproductive organs, thick style 

 and filament adherent high up in the 

 corolla tube and limited range of colors, 

 as representing P. violacea. 



The first double petunia appeared in a 

 private garden in France in 1855 and 

 from this, so far as I have been able to 

 learn, have all other doubles been 

 obtained by artificial fecundation. 



METHOD OF OPERATION 



For the benefit of those in this 

 audience who may be unfamiliar with 

 the method by which double petunias 

 are obtained I will explain, that the 

 double is an imperfect flower and the 

 single is a perfect flower. The un- 

 broken anthers (the pollen-bearing 

 organs) of a single flower are removed, 

 the flower is then covered with gauze 

 or paper until the stigma is ready, the 

 pollen is then applied from a double 

 flower by means of a camel's hair brush 

 and the covering replaced, to prevent 

 the possibility of insect fertilization. 



Such a procedure, however, is entirely 

 too laborious for commercial work. 

 I have never used the coverings but 

 remove the anthers and ]X)llcnize at 

 once from a nearby flower, double and 

 single plants being grown in adjoining 

 plots. 



1 Read before the twelfth annual meeting of the American Genetic Association, at Berkeley, 

 California, August 6, 1915. 

 456 



