224 



PRACTICAL COURSE IN BOTANY 



Cx- - 



332 



333 



FIGS. 331-333. Flower of Lorillard tomato: 331, newly opened bud, showing 

 stage in which the stamens should be removed ; 332, mature flower : ex, calyx ; c, 

 corolla ; s, stamens ; st, stigma ; 333, flower with stamens removed for pollination. 

 (Natural size.) 



of wind -or insects. Watch until seeds are matured. Which flower pro- 

 duces the more seeds or the better ones ? Plant the seeds ; which produce 

 the more vigorous progeny? 



EXPERIMENT 79. CAN A FLOWER BE FERTILIZED WITH POLLEN OF A 

 DIFFERENT KIND ? Dust the stigma of a tulip or a lily, from which the 

 stamens have been removed, with pollen from a narcissus, iris, or amaryl- 

 lis. Cover to protect from wind and insects. Are any seeds produced ? 



Experiments of this kind, to be conclusive, ought to be performed on 

 a sufficient number of plants and through at least three generations. This 

 is hardly practicable for class work, but students who are specially inter- 

 ested in the subject may carry on experiments at home, or supply their 

 place, to some extent, by observations out of doors, if there are any farms 

 or gardens accessible. 



254- Self-fertiliza- 

 tion takes place 

 when a stigma is 

 pollinated from the 

 same flower. Hor- 

 ticulturists have 

 long known that 

 continued self- 

 fertilization, or " in- 

 breeding" as it is 

 called by nursery- 

 men, tends to dete- 

 riorate a stock ; but 



FIGS. 334-335. Seeds of Bartlett pear, 

 the advantage of cross-fertilization : 334 

 fertilized ; 335, self-fertilized, 



showing 

 , cross- 



