The Natural System of Botany. 107 



Sub-Class I. — Exogen^j, or Dicotyledonous Plants. 



Leaves reticulated ; stem with wood, pith, bark, and medullary rays ; cotyle- 

 dons, two or more, placed opposite to each other. 



This sub-class contains all such plants as have seeds com- 

 posed of two or more cotyledons. The species of this latter 

 kind are, however, very few in number, nearly all Exogense, 

 having seeds with only two cotyledons. 



Tribe I. — Angiosperm-e. — Seeds enclosed in a pericarp. 



This tribe includes all such plants as have two cotyledons, 

 and seeds enclosed in apod or shell, or in a coat which proceeds 

 from the germen. Examples : Pea, Chestnut, Larkspur. 



This tribe is divided into Polypetalous, Apetalous, Achlamy- 

 deous, and Monopetalous plants. 



A. PolypetaljE. — (Many-petaled.) — These have a calyx 

 and corolla composed of more than one petal. Ex. : Rose, 

 Buttercup. 



B. Apetal^e. — (Without petals.) — These have a calyx, but 

 no corolla. Ex. : Mignonette, Spurge. 



C. AchlamydejE. — These have neither calyx nor corolla. 

 Ex.: Birch, Willow. 



D. Monopetal^e. — The corolla of these consists of a single 

 petal. Ex. : Trumpet Flower, Morning Glory. 



The three last of these divisions are sub-divided no farther, 

 but the first is separated into Thalamiflorje, in which the 

 stamens are hypogynous, or adhere to the sides of the ovarium ; 

 and Calyciflor^:, in which the stamens are perigynous. 

 Each of these latter is again divided into Apocarpee, in which 

 the carpels are distinct, and Syncarpce, in which they cohere in 

 a solid pericarp. 



Tribe II. — Gtmnospersle. — Seeds destitute of a pericarp. 



The plants of this tribe have neither stigma nor style, the 

 influence of the pollen being communicated directly to the 

 seed through a foramen or orifice. They must not be con- 

 founded with the Gymnospermse of Linnaeus, which all belong 



