CLASSIFICATION. 105 



Ninteenth, stamens and pistils in separate corollas on 

 the same plant, and is called monoecia: cecia signifies 

 house ; hence, mono, one ; ORcia, house. 



Twentieth class, dioecia, two houses; stamens and pis- 

 tils in separate corollas upon different plants or houses. 



The orders of these three last classes, like those of mono- 

 delphia and diadelphia, depend upon the member of stamens. 

 The cryptogamous family, stamens and pistils invisible 

 to the naked eye, form the twenty-first class. The orders 

 of this class are six — filices, musi, hepaticae, algae, lichens, 

 and fungi. 



Section II. — Natural System. 



The natural system differs totally from the artificial, 

 paying but little attention to any one organ, but, regarding 

 the plant as a whole, takes the collective resemblances and 

 groups them by their natural relationships. On this basis 

 it forms them first into classes; these classes are separated 

 into orders, orders are subdivided into genera, and genera 

 into species. 



"We say that exogenous plants constitute one class, endo- 

 genous another, acrogenous a third. The first class is di- 

 vided into two sub-classes: 



1st. Angiosperms, which have pistils of the common 

 kind, in which seed are formed. This includes nearly the 

 whole of the exogens, except the conifers, such as the pine, 

 yew, cedar, etc. These belong to the sub-class number. 



2d. Gymnosperms, with ovules and seeds naked, there 

 being no pistils, or, if any, a mere scale, as in the conifers. 



The cryptogamous plants are subdivided into three 

 classes : 



Class 3. Acrogens, including ferns, horse-tail, and club- 

 moss. 



Class 4. Anophytes, containing mosses and liverworts. 



Class 5. Thallophytes, including lichens, algae, mush- 

 rooms. 



5* 



