INTRODUCTION. 5 
The orders of the fourteenth class, Didynamia^ are 
taken from the situation of the seeds ; and are 
Gymnospermia. . . .naked seeds. 
Angiospermia seeds in a capsule. 
The orders of the fifteenth class, Tet? -adynamia, are 
formed from a difference in the shape of the seed- 
vessel : 
Siliculosa a broad pod. 
Siliquosa a long pod . 
In the classes Monadelphia, T)iadelphia,Polyadelphia t 
and Gynandria, the orders are taken from the number 
of stamens : 
Pentandria 5 stamens. 
Hexandria, &c 6 stamens, &c. 
In the nineteenth class, Syngenesia, the orders are 
taken from the structure of the flower : 
Polygamia sequalis, all the florets alike. 
Polygamia superflua, the florets of the centre perfect or 
united ; those of the margin with pistils only, but all pro- 
ducing perfect seeds. 
Polygamia frustranea, the florets of the centre perfect or 
united; those of the margin, in general, without either 
stamens or pistils. 
Polygamia necessaria, the florets of the centre with stamens 
only; those of the margin with pistils only. 
The classes Moncecia and Dicecia take their orders 
from the number and other peculiarities of the stamens : 
Morrandria 1 stamen. 
Diandria, &c 2 stamens, &c. 
Polyandria 7 stamens. 
Monadelphia stamens united into one set. 
Polyadelphia stamens united into several sets. 
Gynandria stamens upon the pistil. 
In the class Polygamia there are three orders : 
Moncecia. Dicecia. Trioecia- 
