The Origin of Linaria Vulgaris Peloria. 201 



preferably after castration. The seeds collected after 

 this operation are said to give from 25 to 40% double 

 plants the number varying directly with the care with 

 which the castration was carried out. 



Double flowers are also subject to sectorial and bud- 

 variation. A chestnut tree {Acsculus Hippocastaniun) 

 at Geneva, a single branch of which has borne double 

 flowers for many years, ^ is perhaps the best known ex- 

 ample of the latter, whilst our Fig. ^7 gives an interest- 

 ing case of the former. It is a flower of the pure white 

 Ancjjioiie coronaria, "The Bride," which, like the Py- 

 rcthruin, I owe to the kindness of Mr. Krelage. It grew 

 in a bed of the single variety ; the plant which bore it 

 had exclusively single flowers with the exception of 

 this one. On the one half there w^ere stamens only, as 

 is shown by the figure; in the other half, however, the 

 vast majority of stamens were transformed into narrow 

 petals, just as happens all round the stigma in the double 

 form. The single variety frequently exhibits more or 

 less definite traces of doubling, and from these Messrs. 

 Krelage have succeeded in producing a double sort and 

 putting it on the market. But a sectorial variation like 

 that figured has only been observed once in the course 

 of many years. 



§ 20. THE ORIGIN OF LINARIA VULGARIS PELORIA. 



About ten years after the appearance of the first 

 edition of Darwin's Origin of Species (1859) Hof- 



^A. P. DE Candolle, Physiologie vegetate, 1832, II, p. 479, and 

 Alph. de Candolle, Geographie hotanique, 1855, II, p. 1080. This 

 tree stood in the garden of M. Saladin de Bude near Geneva. Many 

 cuttings made from tlie double-flowered branch have been distrib- 

 uted. 



