86 AN INTRODUCTION 
are founded on a Diftin&tion in the Fruit, 
The Title of the firft Order, Gymno/permia, is 
expreffive of fuch Plants as have nated Seeds ; 
and that of the fecond, Angio/permia, of {uch 
as have their Seeds ina Ve//el or Pericarpium. 
The third Order, Polypeta/a, is expreflive of 
fuch Plants as have many Petals: This Or- 
der feems to have been eftablifhed in Favor 
of one Genus of Plants only, the Me/ianthus, 
the Flowers of which are Pelypeta/cus, though 
thofe of all the reft of this Clafs are Mono- 
petalous *, 
CrassXV.TETRADYNAMIA. 
—The two Orders of this Clafs are founded 
on a Diftinétion in the Pericarpium. In the 
firft Order, Si/iculjja, the Pericarpium is a 
Silicula, /:ttle Siliquas; which differs from 
the Sz/:qua in being round, and having the 
Apex of the Diflepiment, which had been 
the Style, prominent beyond the Valves, 
often fo far as to be equal in Length to the 
Silicula. In the fecond Order, Silguofa, 
the Pericarpium is a Sz/igua, which is long 
and without any remarkable Extenfion of 
the Style. 
* This Order is omittad in the Sy/fema Nature, pub- 
lifhed in 1756. See the Note on thi¢ Order in Chapter 
17. 
9 CLAss 
