INTRODUCTION. O 



developed as a natural effect of the laws of nutrition, as 

 takes place in the development of branches, tubercules, 

 offsets, layers, and suckers, for all these bodies may be 

 considered as resulting from the development of germs 

 more or less latent ; or their development requires a 

 preliminary operation, which has been named fecunda- 

 tion, which tends to give the germ a proper life, and 

 this is performed by means of a complicated apparatus 

 of organs, which collectively constitute the flower. Re- 

 production without fecundation, not presenting any 

 organic apparatus which is peculiar to it, will not occupy 

 us in detail before we treat of the functions of plants ; 

 whilst reproduction by fecundation, or sexual reproduc- 

 tion, being caused by numerous and various organs, will 

 henceforth engage all our attention. It has a double 

 claim in this respect, for it is important that all the 

 floral organs should be well understood, not only because 

 they perform one of the principal functions of vegeta- 

 tion, but also because it is upon their constant forms 

 within certain limits, varied ad infinitum in the different 

 species, and remarkable for their symmetry, it is, I say, 

 upon these forms, that all the classification of plants rests. 

 With regard to the general appearance of the organs 

 of fructification, plants are distinguished into Phanero- 

 gamous and Cryptogamous : the former are those 

 which have their flowers visible to the naked eye, more 

 or less symmetrical, and with distinct sexual organs ; the 

 latter are those which have the flowers (if indeed they 

 have any) visible only to the microscope, scarcely, if at 

 all symmetrical, and the sexual organs not distinct. The 

 former comprehend all Exogens, and the greatest part 

 of Endogens ; the latter all Cellulares, and some Endo- 

 gens. "We proceed now to study the organs of Re- 

 production, following this fundamental division of 

 Phanerogamous and Cryptogamous plants. 



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