22 -Principles of Classification . 
fled in a capsule* or seed-vessel* as in foxglove and 
snapdragon. 
Tetradynamia , the 15th class, has also two orders, 
which are determined by the form of the fruit: 1. Sili- 
culosa , in which the fruit is a silicle* or roundish pod, 
as in shepherds-purse, and the common garden cress j 
and 2. Siliquosa, in which the fruit is a siliqua* or long 
pod, as in the pea tribe. 
In the 16th, 17th, and 18th classes* Monadelphia* 
Diadelphia* Polyadelphia* the characters of the orders 
are taken from the number of the stamens* as in the 
first thirteen classes. 
Syngenesia , the 19th class, comprehends five orders, 
the characters of which are taken from the florets of 
which the compound flower is formed, being united or 
separated, barren* fertile. Or abortive. 
The first order Polygamia cequalis, includes those 
plants in which all the florets have both stamens and 
pistils, and produce seeds* as in dandelion. 2. Poly - 
gamia superfua , in which the flowers consist of two 
parts* a disk, or central part, and radii, ot rays* which 
project outward ; the florets of the disk have stamens 
and pistil, and those of the rays have pistil only* but 
each of them produces perfect seed, as in the daisy, 
chamomile, and corn-marygoM. 8. Polygamia Jrus - 
tranea, in which the florets of the disk have stamens 
and pistil, but those of the rays have only an abortive 
pistil* as in blue-bottle. 4. Polygamia necessaria * in 
which the florets of the disk are furnished with stamens . 
only, and those of the radius with pistils only, as in gar- 
den-marygold. 5. Polygamia segregata , in which each 
of the florets has a proper calyx included in one gene- 
ral calyx* as in echinopst or globe-thistle. To this class 
