298 Dr. Lindleifs Natural System of Botany. 



rum, although to a considerable extent artificial, has been almost 

 universally adopted, until within the last few years. 



In this method Dicotyledonous plants are primarily divided into 

 three groups ; the first including those with a polypetalous corolla ; 

 the second, those with a monopetalous corolla ; and the third, those 

 destitute of a corolla. These sections are subdivided, (as also the 

 monocotyledons) by means of characters taken from the insertion of 

 the stamens (or corolla,) whether hypogynous, perigynous, or epigy- 

 nous. The arrangement here pursued, which is too well known to 

 require further notice, is substantially adopted by De Candolle, the 

 difference being more in appearance than reality. Dr. Lindley 

 discarded these subdivisions in the first edition of his work ; but the 

 new distribution of the orders therein proposed possesses few advan- 

 tages, and, indeed appears not to have satisfied the author himself. 

 In the same year with the publication of the work just mentioned, 

 the Ordines Plantarum of Bartling appeared, in which a more nat- 

 ural arrangement of the orders is attempted by the formation of ag- 

 gregate or compound orders, as originally proposed, and in several 

 instances successfully accomplished, by Robert Brown. An analo- 

 gous plan was pursued by Agardh in his Aphorismi Botanici, (1817,) 

 and again in his Classes Plantarum, (1825;) but these attempts, 

 however ingenious, do not seem to have obviated, in any considera- 

 ble degree, the inconveniences of a lineal arrangement. 



We now return to our author, whose views upon this subject have 

 been materially modified since the original publication of his Intro- 

 duction to the Natural System. The method now employed was 

 first sketched in the Nixus Plantarum, (1832,) and afterwards in 

 the Key to Structural, Physiological, and Systematic Botany,* 

 (1835,) and is more fully developed and illustrated in the work 

 before us. He now admits, as we have already seen, five primary 

 classes, two of which, however, are much smaller than the others 

 and of subordinate importance, and may be considered as transition 

 classes, viz. Gymnospermce, which connect Exogens with the higher 

 Acrogens, and Rhizantha, which form the transition from Endogens 

 to Acrogens of the lowest grade. The great class Exogena (Di- 

 cotyledones of Jussieu,) is divided into three subclasses, viz. 



* This excellent little work consists of an augmented edition of the author's 

 Outlines of the first principles of Botany, with a revised translation of the Nixus 

 Plantarum. 



