1 1 8 GOOD FROM CROSSING. Chap. XVII 



pollen of V. thapsus ; but the flowers could not be fertilised by their 

 own pollen. Kolreuter, also, 74 gives the case of three garden plants 

 of Verbascum phoeniceum, which bore during two years many flowers ; 

 these he fertilised successfully with the pollen of no less than 

 four distinct species, but they produced not a seed with their own 

 apparently good pollen ; subsequently these same plants, and others 

 raised from seed, assumed a strangely fluctuating condition, being 

 temporarily sterile on the male or female side, or on both sides, and 

 sometimes fertile on both sides; but two of the plants were perfectly 

 fertile throughout the summer. 



With Reseda odorata I have found certain individuals quite sterile 

 with their own pollen, and so it is with the indigenous Reseda hdea. 

 The self-sterile plants of both species were perfectly fertile when 

 crossed with pollen froni any other individual of the same species. 

 These observations will hereafter be published in another work, in 

 which I shall also show that seeds sent to me by Fritz Mailer 

 produced by plants of Esckschdtzia oalifornica which were quite 

 self-sterile in Brazil, yielded in this country plants which were only 

 slightly self-sterile. 



It appears 75 that certain flowers on certain plants of Lilium 

 rind iilum can be fertilised more freely by pollen from a distinct 

 individual -than by their own. So, again, with the varieties of the 

 potato. Tinzmann, 76 who made many trials with this plant, says 

 that pollen from another variety sometimes "exerts a powerful 

 " influence, and I have found sorts of potatoes which would not 

 " bear seed from impregnation with the pollen of their own flowers 

 " would bear it when impregnated with other pollen." It does 

 not, however, appear to have been proved that the pollen which 

 failed to act on the flowers own stigma was in itself good. 



In the genus Passifiora it has long been known that several 

 species do not produce fruit, unless fertilised by pollen taken from 

 distinct species : thus, Mr. Mowbray 77 found that he could not get 

 fruit from P. (data and racemosa except by reciprocally fertilising 

 them with each other's pollen ; and similar facts have been observed 

 in Germany and France. 78 I have received two accounts of P. 

 guadrangularis never producing fruit from its own pollen, but 

 doing so freely when fertilised in one case with the pollen of P. 

 candea, and in another case with that of P. edulis. But in three 



74 'Zweite Fortsetzung,' s. 10; developed :' Journal Asiatic Soc. Ben- 



'Dritte Forts.,' s. 40. Mr. Scott like- gal,' 1867, p. 150. 



wise fertilised fifty-four rlowers of T5 Duvernoy, quoted by Gartner, 



Verbascum phceniceum, including two ' Bastarderzeugung.' s. 334. 



varieties, with their own pollen, and 76 ; Gardener's Chronicle,' 1846, p. 



not a single capsule was produced. 183. 



Many of the pollen - grains emitted 77 ' Transact. Hort. Soc.,' vol. vii., 



their tubes, but only a few of them 1830. p. 95. 



penetrated the stigmas ; some slight 78 Prof. Lecoq. ' De la Fecondation,' 



effect however was produced, as many 1845. p. 70; Gartner, ' Bastarder- 



of the ovaries became somewhat zeugung,' s. 64. 



