200 Observation of the Origin of Varieties. 



nosa).^ For instance, 80% is the figure given for Dian- 

 thiis CaryophylluSy^ and double varieties of Campanula 

 are said always to produce a certain number of single 

 plants. In the case of double stocks one may reckon on 

 between 50-60% double offspring according to the treat- 

 ment and selection of the seed. Pot culture favors "doub- 



1 



mg. 



"3 



The transformation of stamens into petals often goes 



so far that no pollen is 

 formed. When this oc- 

 curs the stigma of the 

 double flower must be 

 fertilized with the pol- 

 len of a single flower 

 or left to be pollinated 

 by insects. The result 

 is that the race gives 

 rise to both forms every 

 year. For instance Pa- 

 paver nudicaule auran- 

 tiacum plenum, the seeds 

 of which give rise to 

 between 40 and 60% of 

 double -flowered speci- 

 mens every year. It is 

 the other way round 

 with the double Petunia whose capsules are usually mal- 

 formed ; but they develop a few stamens, with the pollen 

 from which the stigmas of single flowers are dusted, 



^Ibid. 



^ Seed catalogue of D. Sachs, Quedlinburg, 1890-91. (Dianfhus 

 Caryophylliis c. ft. Margaritae, novelty 1889). 



^ Chate, Culture pratique des Giroftees. Nobbe. Botaji. Central- 

 blatt, Vol. XXXII, 1887, p. 253. 



Fig. 37. Anemone coronaria, "The 

 Bride." Double on one side, single 

 on the other. From the cultures of 

 Messrs. E. H. Krelage & Son of 

 Haarlem. 



