SECT. I. ORGANOGRAPHY AND GLOSSOLOGY. 



the fangs of a serpent's tooth. The 

 bristles have sometimes a stellate 

 form {fig. 21. a) ; and sometimes 

 the pubescence is composed of little 

 plates or scales (6). 



(32.) Complex Organs. Although the epidermis and 

 several of the other investing organs are of a compound 

 character, they are still constructed in a much more 

 simple manner than the organs which they invest. We 

 have proposed, therefore (art. 28.), to separate- the 

 latter under the name of " complex organs," which 

 will include all that have been already enumerated 

 under the name of external organs (art. 9-)' together 

 with various appendages to be found on some of them. 

 These latter are not so generally noticed by casual ob- 

 servers ; but it will be necessary for us presently to de- 

 scribe them, when we treat of the forms and structure of 

 these organs themselves. But we shall here postpone 

 for a while the descriptive details of these organs, in 

 order that the reader may first obtain some general 

 notions of the three great natural divisions under which 

 all plants may be arranged. Although this method of 

 treating our subject may seem to indicate a great want 

 of system, it appears to us highly convenient that every 

 one should be acquainted with these divisions as early as 

 possible before he enters on certain details which can- 

 not be so well appreciated or discussed without an 

 occasional reference being made to them. It must be 

 remembered that we have not proposed to ourselves any 

 very methodical discussion of the several departments 

 of our science, which would have required a series of 

 separate treatises, but that we aim chiefly at conducting 

 the general reader, by such steps as may seem suffi- 

 ciently adapted to the purpose, to the ready comprehen- 

 sion of some of the best established facts in vegetable 

 physiology, and to give him an idea of what botany 

 proposes to attempt. 



(33.) Primary Groups. We apply the term " spe- 

 cies" to an assemblage of individuals which have sprung 



