PERSPIRATION OF PLANTS. 21 



Crassula punctata, lactea, Cotyledon, Sec. which 

 have their surfaces covered with round points 

 visible to the naked eye. Upon raising the 

 cuticle, he observed each of these points to be 

 formed by a pencil of fibres terminating here, after 

 having traversed the parenchyma of the leaf. In 

 plants with leaves very fibrous, such as Camellia 

 japonica, and Celastrus buxifolius, &c. he found 

 about sixty pores in the space of two square milli- 

 metres (about a square line) while there appeared 

 only from five to eight within the same extent on 

 the cuticle of several succulent plants, that have 

 leaves much less fibrous. 



In general, no such pores are to be found upon 

 the stalks, except in such as are of a soft texture, 

 approaching to that of most leaves ; and upon 

 several of those which have no leaves, as the 

 species of Ephedra, Stapelia, &c. There are none 

 to be seen upon the leaves of Cuscuta europcea, 

 which singular plant, when immersed in water, ac- 

 cording to the observations of M. Decandolle, 

 affords no gas whether exposed to light or 

 darkness. 



