PRELIMINARY DISCOURSES. 



the aspect of the superior plants, they have on that account been 

 denominated Anophytes, comprising the Mosses and Hepaticae. 



The plants of the third and lowest cryptogamous Class com- 

 posed of parenchyma alone, or mere cellular masses, or expansions, 

 without any marked distinction of root, stem, or foliage, are called 

 Thallophytes. This Class consists mainly of Lichens, Fungi, and 

 Algae, or Sea-weeds, some of which present the simplest forms of 

 vegetable existence. 



"In an exposition of the natural system, some authors (such as 

 JUSSIEU and ENDLICHER) commence with the lower extremity of 

 the series, and end with the higher; while others (as DE CANDOLLE) 

 pursue the opposite course, beginning with the most perfect flower- 

 ing plants, and concluding with the lowest grade of flowerless 

 plants. The first mode possesses the advantage of ascending by 

 successive steps from the simplest to the most complex structure ; 

 the second, that of passing from the most complete and best under- 

 stood to the most reduced and least known forms; or, in other 

 words, from the easiest to the most difficult ; and is therefore the 

 best plan for the student."* 



These very imperfect preliminary Discourses are submitted to 

 the youthful reader in the hope, and for the simple purpose, of 

 Commending to his favor the study of the interesting objects here- 

 inafter described ; and in the firm belief, moreover, that such study 

 will prove an unfailing source of both pleasure and profit, to all 

 Who prosecute it with success. 



And now having reached the allotted limit of three score and 

 ten the Author would take an affectionate leave of his young 



* The opinion cited in the text, is that of Prof. A. GRAY. It is sustained by 

 AUGUSTS DE SAINT-HILAIRE, in the following passage, referring to the same sub- 

 ject: " Devons-nous, & 1'exemple de JUSSIEU, commencer cette s6rie par les 

 plantes les plus imparfaites, ou faut-il, comme M. DE CANDOLLE, la commencer par 

 celles qui sont le plus elevens dans 1'ordre des developpmeuts ? II est incontest- 

 able que nous ne saurions nous former une idee juste d'un corps qui a 6prouv6 

 quelques suppressions, si sous ne 1'avonn vu dans son integrite, ou, du moins, si 

 nous n'avons vu sans aucune suppression quelque corps analogue. Les botanistea 

 d'un pays oft. il n'existerait que des Graminees ou des Polygala pourraient, sans 

 doute, decrire les caracteres de leurs fleurs, mais ils ne sauraient s'expliquer 

 la veritable structure de cea mgmes fleurs, ils n'en comprendraient point la 

 symetrie. Nous mettrons done less plantes les plus completes & la tete de la 

 serie puisque celles la seules peuvent nous expliquer les autres ; ce sera proceder 

 du counu i 1'inconnu, marche que 1'on suit dans toutes les sciences. Le patre, 

 qui connait seulement sa cabane, ne verra, dans de nobles mines, que d'informes 

 amas de pierres ; mais un architecte habile, qui aura soigneusement observ6 une 

 foule de constructions diverges, aura a peine jete les yeux sur ces restes dedaignes 

 de 1'ignorant, qu'il se representera 1'edifice auquel ils ont appartenu, qu'il pourra 

 toeme nous tracer le plan de cet edifice." 



