254 



PHYTOKOMY. 



corresponding to the pattern which properly belongs to each 

 plant 



That electricity performs an important part in impregna- 

 tion, has long been suspected ; and the contraction of electri- 

 cal matters in the blossom, and in the parts of fructification, 

 seems to favour this idea. 



382. 



As we thus consider the stimulus of the pollen to be a ne- 

 cessary condition of the evolution of seed from the ovula, we 

 must at the same time defend ourselves against both the an- 

 cient and later objections to this doctrine, and must be pre- 

 pared to encounter the reproach of having taken a partial 

 view. 



It is true that dicHnous plants often seem to bear fruit 

 without having been impregnated by pollen. Not only an- 

 cient pretended observations respecting the setting of the 

 fruit in the female hemp plants, after the male plants had 

 been taken away, but more recent experiments, which have 

 the appearance of having been carefully made, have bred a 

 doubt respecting the necessity of impregnation by pollen to 

 the evolution of the seed (Spallanzani, Fisica animale e vege- 

 tabile.) Supposing these experiments to have been always 

 made with indisputable exactness, fidelity, and care ; suppo- 

 sing also that perfect seed has been obtained from female 

 plants of Spinage, Hemp, and Mercury, which were com- 

 pletely isolated, the reason of this is to be sought in the fre- 

 quently androgynous nature of diclinous plants. For Glei- 

 chen has shewn respecting Spinage, Schkuhr respecting Mer- 

 cury, and Kastner respecting Willows, that female plants of- 

 ten bear hermaphrodite blossoms, at least that they are an- 

 drogynous. Something similar must take place with respect 

 to Hops ; for when only female plants are set, male plants 

 are found to have risen among them ; (Thaer, Grundsatze 

 der rationellen Landwirthshaft.) 



