HYBRIDIZATION. 131 



The pollen or fecundating matter is however wonderfully 

 organized, so as to facilitate its action on the pistils. The 

 granules of which it is composed are so small and nu- 

 merous, that they form a fine, light powder, which is easily 

 transported by the winds to a very considerable distance 

 from the plant. Instances might be cited of dioecious trees, 

 such as palms and pistachio nuts, the females of which 

 have been fecundated by pollen from male trees separated 

 from them a distance of several leagues.* The wind 

 drives the pollen far and near, and the air becomes some- 

 times so charged with it, that the rain in falling brings it 

 in considerable quantities to the ground, producing the so- 

 called sulphur showers of which we read about in history. 

 There is no doubt also, that the bee and other insects in 

 search of honey, convey the pollen from the stamens to 

 the pistils, in unisexual plants. 



HYBRIDIZATION IN PLANTS AND ANIMALS. 



If pollen is conveyed by means of the atmosphere and 

 insects, it must happen that plants will occasionally hybri- 

 dize, or the pollen of one species will sometimes fertilize 

 the ovules of another species of the same genus. The 

 seeds thus produced give rise to individuals of an inter- 

 mediate character, but which are unable to perpetuate 

 themselves ; or if they have that power, lose it in the second 

 or third generation. 



The analogies between animals and plants are in no in- 

 stances more striking, than in their power of hybridizing, 

 and in the similarity of the restrictions imposed by all-pro- 

 vident nature on the exercise of this function. In both, it 



* Precis de Botanique et Physiologic Vegetale, par Achille Richard, 

 page 254. 1852. 



