242 



CLASS DIDYXAMIA. 



LECTURE XXXII. 



CLASS XIII DIDYNAMIA, AND XIV TETRADYNAMIA. 



THE two classes which are to afford subjects for our present 

 observations, are founded upon the number and relative length 

 of the stamens. 



In distinguishing their orders, the number of styles is not re- 

 garded, but new circumstances of distinction are introduced, 

 viz. the seeds" being enclosed in a capsule, or destitute of any 

 such covering"; and the comparative length of pods. 

 Class Didijnamia. 



Fig. 117. 



This class has flowers with four sta- 

 mens, two of which are longer than 

 the other two ; plants of this class are 

 in general easily distinguished; the 

 stamens stand in pairs ; the outer pair 

 being longer, the inner pair shorter, 

 and converging. 



The class contains two orders, Gym- 

 nospermia (naked seeds), and Angio- 

 sperinia (seeds covered). 



Gymnospermia. 



In the 1st order, which contains plants with^bwr naked seeds, 

 the flowers grow in whorls or rings, having a square or angled 

 stem, and leaves opposite. The corollas are labiate, having 

 divisions resembling lips, and they are also called ringent, or 

 gaping, because the lips appear to be open. The calyx is 

 either in five equal parts, or consists of two lips. 



At Fig. 117, a, is a flower of the genus Teucrium (german- 

 der) ; the corolla is ringent ; the upper lip is two-cleft ; the 

 lower lip is three-cleft; the stamens and pistils are incurved; 

 the stamens are expert through the cleavage on the upper side ; 

 b, shews the pistil with its four uncovered or gymnospermous 

 seeds. 



The plants of this order are mostly aromatic ; very few are 

 poisonous. We find here the Mint, Lavender, Penny-royal, 

 Balm, and others of a similar nature. They are included un- 

 der the natural family Labiata. For more particular remarks 



Classes 13th and 14th, on what founded Their orders Class Didynnmia 

 Order Gymnospermia. 



