78 AN INTRODUCTION 



Vitex, Duranta and Resleria. 6. Such as have mo- 

 nopetalous flowers, and the calyces uiultifid, of which 

 there are 'three, viz. Hyobanche, Cymbaria, and 

 Thunbergia. 7- Such a& have flowers with many 

 petals, of which there is one genus, viz. Meiianthus, 



CHAP. XVIII. 



OF THE FIFTEENTH CLASS TETRADYNAMIA*. 



THIS Class consists of such plants as bear herma- 

 phrodite flowers, furnished with six stamina, two of 

 which are shorter than the rest, oy which last cir- 

 cumstance it may be distinguished from the sixth 

 class, whose flowers have six equal stamina. The 

 flowers of this class are of a particular structure, an- 

 swering to the character following. 



Characters of the Class TETRADYNAMIA. 



CALYX A perianthium tetraphyllous and oblong ; 

 the leaves of which are ovato-oblong, concave, ob- 

 tuse, conniving, gibbous downwards at the base, the 

 opposite ones equal and deciduous. Within the 



* These are the Cruciformes, (cross-shaped flowers) of 

 Tournefort ; and Siliculosae and Siliquosae (plants that hare 

 a Silicula and Siliqua) of Ray, Hist. Plant. 777. This class 

 is truly natural, and has been assumed as such by all syste- 

 matists, though individuals have often added one or more ge- 

 nera to it, contrary to nature. Linnaeus thinks he has given 

 no wrong one, unless it be the Cleome. The distinction into 

 Siiiculose and Siliquose is admitted by all. The plants are 

 held to be antiscorbutic and diuretic. The taste in most is 

 watery, mixed with a sharpness. They commonly lose their 

 quality when .dried. The essential character of the several ge- 

 nera in this class depends commonly on the situation of the 

 nectariferous Glandule. 



