34 



sind, dass die Bestâubung sich selbst ûberlassen wurde. 

 Die Môglichkeit ist also nicht ausgeschlossen, dass in einigen 

 Blûten die Bestâubung nur unvollstandig stattgefunden hat; 

 die spontané Befruchtung ist nicht immer so vollkommen 

 als die absichtliche. 



Bei Adonis aestivalis. „According to Professer H. 

 «Hoffmann, this plant is proterandrous; never- 

 „theless it yields plenty of seeds when protec- 

 „ted from insects. Fifteen flowers were crossed 

 „and ail produced fruit, containing on an ave- 

 „rage 32.5 seeds; nineteen flowers were fertili- 

 „sed with their own pollen, andttieylikewise 

 „all yielded fruit, containing a rather larger 

 „average of 34.5 seeds; or as 100:106. 



„The average height of the four crossed plants 

 „is 14.25 and thatofthe four self-fertilised plants 

 ,,14.31; or as 100:100.4; so that they were in fact 

 „of equal height." 



Bei Nicotiana tabacum: „Out of six trials with 

 „crossed and self-fertilised plants, belonging to 

 „three successive générations, in one alone did 

 „the crossed show any marked superiority in 

 „height over the self-fertilised; in fourofthe 

 „trials they were approximately equal; and in 

 „one the self-fertilised plants were greatly su- 

 „perior to the crossed. In no case did the cap- 

 „sules from flowers fertilised with pollen from 

 „a distinct plant yield many more, and some- 

 „times they yielded much fewer seeds than the 

 „capsules from self-fertilised flowers 



„(P. 210). Taking the plants of the three gene- 

 „rations altogether, the crossed show no supe- 

 „riority over the self-fertilised, and I can ac- 

 „count for this fact only by supposing that 

 „with this species, which is perfectly self-fertile 



