70 NATURAL CLASSES. 



kind of genealogical tree, 4th by a triple con- 

 centric cercle, divided in rays, the inner circle 

 being the cellular plants, the outer or largest 

 the Exogenous plants and trees, 5th by a triple 

 series or 3 columns one for each great series, 

 with lines accross to connect affinities. 



Few of these excellent modes of elucidation 

 have been employed as yet, the best in use are 

 the Analytical and Synthetical tables ; but all 

 the serial modes whether circular or linear or 

 triple, are all inadequate and imperfect. This 

 explanation was needful as an apology for having 

 used this vulgar mode even here ; but I had 

 made a complete Botanical map as early as 

 181 5. Such botanical illustrations may exercise 

 the ingenuity of Botanists well skilled in botan- 

 ical affinities ; which are the highest results of 

 phytographical knowledge, as stated by Jussieu 

 — Their relative value, importance and per- 

 manency, must equaly be ascertained, and there- 

 by we invariably fix the botanical groups, what- 

 ever be the names we may apply to them, or 

 place we may allow them. 



The general aspect and organs of plants must 

 also be studied and attended to, more than 

 usual at least; and experienced botanists can 

 often detect or conjecture the natural Classes 

 and Orders of many plants without flowers by 

 such means, called the habit or general form. 

 But as this indication is liable to many excep- 

 tions and anomalies, it must always give way 

 to the floral certitude. 



Meantime I venture to propose the following 

 arrangement, which I have devised, and found 

 very useful in practice ; as it will be indispensa- 

 ble in the study of fossil Botany, or the primi- 

 tive forms of vegetable organization. 



