150 



STEKILITY. 



Chap. XVIII. 



the female organs struck with sterility, whilst the male organs 

 remain perfect. Dianthw japonicus, a Passiflora, and Nicotiana, 

 have been described by Gartner 89 as being in this unusual con- 

 dition. 



Monstrosities as a cause of sterility. — Great deviations of structure, 

 even when the reproductive organs themselves are not seriously 

 affected, sometimes cause plants to become sterile. But in other 

 cases plants may become monstrous to an extreme degree and yet 

 retain their full fertility. Gallesio, who certainly had great ex- 

 perience, 90 often attributes sterility to this cause; but it may be 

 suspected that in some of his cases sterility was the cause, and not 

 the result, of the monstrous growths. The curious St. Valery apple, 

 although it bears fruit, rarely produces seed. The wonderfully 

 anomalous flowers of Begonia frigida, formerly described, though, 

 they appear fit for fructification, are sterile. 91 Species of Primul i 

 in which the calyx is brightly coloured are said 92 to be often sterile, 

 though I have known them to be fertile. On the other hand, 

 Verlot gives several cases of proliferous flowers which can be pro- 

 pagated by seed. This was the case with a poppy, which had 

 become monopetalous by the union of its petals. 93 Another extra- 

 ordinary poppy, with the stamens replaced by numerous small 

 supplementary capsules, likewise reproduces itself by seed. This 

 has also occurred with a plant of Saxifraga geum, in which a series 

 of adventitious carpels, bearing ovules on their margins, had been 

 developed between the stamens and the normal carpels. 94 Lastly, 

 with respect to peloric flowers, which depart wonderfully from the 

 natural structure, — those of Linaria vulgaris seem generally to be 

 more or less sterile, whilst those before described of Antirrhinum 

 mujus, when artificially fertilised with their own pollen, are 

 perfectly fertile, though sterile when left to themselves, for bees are 

 unable to crawl into the narrow tubular flower. The peloric 

 flowers of Corydab's solida, according to Godron, 95 are sometimes 

 barren and sometimes fertile ; whilst those of Gloxinia are well 

 known to yield plenty of seed. In our greenhouse Pelargoniums, 

 the central flower of the truss is often peloric, and Mr. Masters 

 informs me that he tried in vain during several years to get seed 

 from these flowers. I likewise made many vain attempts, but some- 

 times succeeded in fertilising them with pollen from a normal 



85 ' Bastarderzeugung,' s. 356. 



00 'Teoria della Riproduzione,' 

 1816, p. 84; 'Traite du Citrus,' 1811, 

 j>. 67. 



91 Mr. C. W. Crocker, in ' Gard. 

 Chronicle,' 1861, p. 1092. 



92 Verlot, 'Des Varietes,' 1865, 

 p. 80. 



93 Verlot, ibid., p. 88. 



94 Prof. Allman, Brit. Assoc, 

 quoted in the ' Phytologist,' vol. ii. 



p. 483. Prof. Harvey, on the autho- 

 rity of Mr. Andrews, who discovered 

 the plant, informed me that this 

 monstrosity could be propagated by 

 seed. With respect to the poppy, see 

 Prof. Goeppert, as quoted in ' Journa' 

 of Horticulture,' Julv 1st, 1863, p. 

 171. 



95 'Comptes Rendus,' Dec. 19th, 

 1864, p. 1039. 



