THE LIXX^AN SYSTEM. 151 



ments clearly call for a more extensive knowledge of the anatomy of plants than that 

 upon which the sexual system was founded, and should more nearly approach to a 

 natural association of these products of creation. Systems have been founded which 

 are intended to answer to all the three above-mentioned requirements, and have been 

 termed natural system, in opposition to that of Linnseus, which, from its narrow basis, 

 was known as the artificial system. It is evident, however, that the natural systems 

 are the more desirable, and they are rapidly superseding the Linnaean arrangement ; but 

 as we are addressing ourselves to an extended circle of readers, we deem it a duty, first, to 

 make them acquainted with the latter, and then to give them an insight into the former. 



LINNAEAN SYSTEM. 



The Linnaean system is based upon the existence of sexual organs, and is varied 

 according to the number and position of each division of these organs. In consists of 

 classes and orders; the former associated chiefly with the stamens, and the latter 

 with the pistils. 



There are 24 classes, of which 23 belong to flowering and one to flowerless plants. 

 A reference to the annexed plan will show that the first eleven classes are named 

 according to the number of the stamens viz., from 1 to 12 stamens ; the last, however, 

 admitting also of more than 12 stamens. The 12th and 13th classes have an indefinite 

 number of stamens ; but in the former (Icosandria) they are all attached to the calyx, 

 whilst in the latter they remain free from their origin in the receptacle. This difference 

 appears to be a trifling one, but it is constant, and in practice, moreover, is well denned. 

 The 14th and 15th classes depend upon the number and relative length of the stamens? 

 there being two long and two short stamens in the former, Didynamia, and four long 

 and two short ones in the latter, Tetradynamia. In the 16th, 17th, and 18th classes, the 

 stamens are associated into bundles ; one bundle in Monodelphia, two in Diadelphia, and 

 three or more in Polydelphia. In the 19th class the stamens are also united into one 

 bundle, Syngenesia; but they thus form a tube through which the pistil passes. The 

 class termed Ggnandria, indicates that the stamen and pistils are united together. 

 The 21st, 22d, and 23d classes, comprehend plants in which the male and female parts 

 are not met with together in the same flower. Thus in Moncecia separate male and 

 female flowers are found on the same plant, whilst in Dicecia one plant is entirely male 

 and another exclusively female ; and in Polygamia both bi-sexual and uni-sexual flowers 

 grow on the same tree. The 24th and last class embraces an heterogeneous assemblage 

 of low organized plants, having this one property in common, that their sexual organs 

 are concealed, whence the term Cryptogamia. 



The foregoing 24 classes are divided into numerous orders. The orders of the first 

 13 classes are based upon the number of the pistils, which vary from one, Monogynia, 

 to twelve, Lodecagynia, and more than twelve, Polygynia ; whilst the 16th, 17th, 18th, 

 20th, 21st, and 22d classes are subdivided into orders according to the number of their 

 stamens. The nature of the ovary determines the orders in the 14th and 15th classes. 

 The 23d class, or that termed Polygamia, has but one order, and that depends upon the 

 fact that certain of the flowers on the same plant are bi-sexual, whilst others are uni- 

 sexual. The 19th class, or Syngenesia, has orders depending upon the forms and 

 fertility of the florets ; and the last one, Cryptogamia, is subdivided according to the 

 families of which it is composed. 



The following tables contain a complete summary of the Linnsean plan of classi- 

 fication. The reader will understand that the table reads across the two pages. 



