Chap. XVIII. DOUBLE FLOWERS. 151 



flower of another variety; and conversely I several times fertilised 

 ordinary flowers with peloric pollen. Only once I succeeded in 

 raising a plant from a peloric flower fertilised by pollen from a 

 peloric flower borne by another variety ; but the plant, it may be 

 added, presented nothing particular in its structure. Hence we 

 may conclude that no general rule can be laid down; but any 

 great deviation from the normal structure, even when the repro- 

 ductive organs themselves are not seriously affected, certainly often 

 leads tc sexual impotence. 



Double Floiuers. — When the stamens are converted into petals, 

 the plant becomes on the male side sterile ; when both stamens 

 and pistils are thus changed, the plant becomes completely barren. 

 Symmetrical flowers having numerous stamens and petals are the 

 most liable to become double, as perhaps follows from all multiple 

 organs being the most subject to variability. But flowers furnished 

 with only a few stamens, and others which are asymmetrical in 

 structure, sometimes become double, as we see with the double 

 gorse or Ulex, and Antirrhinum. The Composite bear what are 

 called double flowers by the abnormal development of the corolla of 

 their central florets. Doubleness is sometimes connected with 

 prolifi cation, 96 or the continued growth of the axis of the flower. 

 Doubleness is strongly inherited. No one has produced, as Lindley 

 remarks, 97 double flowers by promoting the perfect health of the 

 plant. On the contrary, unnatural conditions of life favour their 

 production. There is some reason to believe that seeds kept during 

 many years, and seeds believed to be imperfectly fertilised, yield 

 double flowers more freely than fresh and perfectly fertilised seed. 98 

 Long-continued cultivation in rich soil seems to be the commonest 

 exciting cause. A double narcissus and a double Anthemis nobilis, 

 transplanted into very poor soil, has been observed to become 

 single ; " and I have seen a completely double white primrose 

 rendered permanently single by being divided and transplanted 

 whilst in full flower. It has been observed by Professor E. Morren 

 that doubleness of the flowers and variegation of the leaves are 

 antagonistic states ; but so many exceptions to the rule have lately 

 been recorded, 100 that, though general, it cannot be looked at as 

 invariable. Variegation seems generally to result from a feeble or 

 atrophied condition of the plant, and a large proportion of the 

 seedlings raised from parents, if both are variegated, usually perish at 

 an^early age ; hence we may perhaps infer that doubleness, which is 



96 'Gardener's Chronicle,' 1866, p. can Journ. of Science,' vol. xxiii. p. 

 681. 47 ; and Verlot, ' Des Vaiietes,' 1865, 



97 < Theory of Horticulture,' p. 333. p. 84. 



93 Mr. Fairweather, in ' Transact. ,J ' J Lindley's ' Theory of Horticul- 



Hort. Soc.,' vol. iii. p. 406 : Bosse, ture,' p. 3 3. 



quoted by Bronn, 'Geschichte der 10 ° ' Gardener's Chronicle,' 1865. p. 



Natur,' B. ii. s. 77. On the effects of 626 ; 1866, pp. 290, 730 ; -and Verlot, 



the removal of the anthers, see Mr. ' Des Varietes,' p. 75. 

 Leitner, in Siliiman's ' North Ameri- 



