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Ch. XXXVI.] 



THE HYBRIDISATION OF PLANTS. 



309 



materiallj tlie process of fructification.^ Few persons need 

 be reminded tliat the stamens in certain plants grow on 

 different blossoms from the pistils ; and, nnless the summit of 

 the pistil be touched with the fertilising dust^ the fruit does 



lie seed arrive at maturity. It is by the help 

 and other insects^ that the development of 



moths 



they have 



many 



from the stamens 



m 



A vast majority of plants are 



m 



yet Mr 



Knip-ht 



imen 



has proved expe 



intermarriage of two separate individuals gives more vigour 



and fertility to the oifspring than if the female organs are 



males of the same 



The 



whole arrangement of the flower may seem to be made for 

 the purpose of close interbreeding, and yet insects and other 

 means are employed by nature for crossing the hermaphrodite 

 with another individual of the same species. 



How often, during the heat of a summer's day, do we see 

 the males of dioecious plants, such as the yew-tree, standing 

 separate from the females, and sending off into the air, upon 

 the slightest breath of wind, clouds of buoyant pollen ! That 

 the zephyr should so rarely intervene to fecundate the plants 

 of one species with the anther-dust of others, seems almost to 

 reahse the converse of the miracle believed in by the credulous 

 herdsmen of the Lusitanian mares — 



Ore omnes versse in Zephyrum, stant rupibus altis 



Exceptantque leves auras: et ssepe sine uUis 

 Conjugiis, yeuto gravidse, mirabile dictu.f 



Mr 



is fertilised 



by the wind, it never has a gaily coloured corolla ; but when 

 its fertilisation depends on the aid of insects, the flowers are 

 conspicuous in colour and size, evidently in order to attract 



their observation. + 



When we consider the facility with which the skilful 



* See Barton ' On Geography of 

 Plants,' p. 67. 



t Georg. lib. iii. 273. 



i Origin of Species, 4th edition, p. 239 



