192 FUNCTIONS OP THL 



fection in different flowers at different times, so that 

 the anthers of one may impregnate the stigmas of anoth- 

 er, whose stamens were abortive, or long since wither- 

 ed. The same thing happens in other instances. Lin- 

 naeus mentions the Jatropha urens as producing flowers 

 with stamens some weeks in general before or after the 

 others. Hence he obtained no seed till he preserved 

 the pollen a month or more in paper, and scattered it on 

 a few stigmas then in perfection. There can be no 

 doubt that, in a wild state, some or other of the two 

 kinds of blossoms are ripe together, throughout the 

 flowering season, on different trees. 



A similar experiment to that just mentioned was made 

 in 1749 upon a Palm-tree at Berlin, which for want of 

 pollen had never brought any fruit to perfection. A 

 branch of barren flowers was sent by the post fromLeip- 

 sic, twenty German miles distant, and suspended over 

 the pistils. Consequently abundance of fruit was ri- 

 pened, and many young plants raised from the seeds. 



Tournefort and Pontedera supposed the pollen to be 

 of an excrementitious nature, and thrown off as super- 

 fluous. But its being so curiously and distinctly organ- 

 ized in every plant, and producing a peculiar vapour 

 on the accession of moisture, shows, beyond contra- 

 diction, that it has functions to perform after it has left 

 the anther. The same writers conceived that the sta- 

 mens might possibly secrete something to circulate from 

 them to the young seeds ; an hypothesis totally subvert- 

 ed by f.very flower with separated organs, whose sta- 

 mens could circulate nothing to germens on a different 

 branch or root ; a difficulty which the judicious Tour- 

 nefort perceived, and was candid enough to allow. 



Both the conjectures just mentioned vanish before 

 one luminous experiment of Linnaeus, of all others the 



