No. 597] EXPERIMENTS WITH PETUNIA 



551 



ever, through the assistance of the authorities at Kew 

 and of Sir Reginald Tower in Argentina, to whom I am 

 much indebted, seed was obtained of wild plants of P. 

 nyctaginiflora and also of two new unnamed wild forms 

 (species, both white-flowered), all of which had been col- 

 lected most kindly by M. Thays, director of the Botanic 

 Garden at Buenos Aires. An entirely new stock of 

 double material differing in nature as well as in origin 

 from that previously employed was also now available. 

 This was raised from 



(1) seed of a plant exhibited at the Conference on Genet- 



ics held in Paris in 1911, which had some flowers 

 double and others apparently of a normal single 

 structure. This plant had appeared in the grounds 

 of the establishment of MM. Vilmorin-Andrieux et 

 Cie at Verrieres-le-Buisson. Some seed harvested 

 from the single flowers, together with a small 

 quantity obtained from the doubles was later most 

 courteously forwarded to me by Dr. Haagedoorn ; 



(2) seed sent to me by Mrs. Francis of Ventura, Cali- 



fornia, of an interesting new strain of seed-produc- 

 ing doubles which she had succeeded in raising. 8 

 The South American seed samples gave plants of uni- 

 form type in the case of the two new forms, each presum- 

 ably being a distinct species. One of the two (referred to 

 below as P.x.), the seed of which had been collected in 

 Cordova, was crossed with pollen from a double raised 

 from the seed of one of the single flowers on Haagedoorn 's 

 half-and-half plant, and also with two seed-giving doubles 

 of the Ventura strain. Each F 1 family showed a mixture 

 of singles and doubles. In the case of the former cross a 

 large number of semi-double plants with the supernu- 

 merary petaloid structures small or few in number, were 

 also obtained. The numbers recorded are given on page 

 552. 



These 5 seed-parents as well as other individuals tested 

 proved quite self fertile and set a good quantity of seed 

 when self-pollinated. 



t For an account of this strain see Mrs. Myrtle Francis [Shepherd] on 

 "Doutle Seeding Petunias," of Heredity, Oct., 1915. 



