ANATOMY OF PLANTS. 213 



considerable swelling of the parts which lie between them, so 

 that, upon the slightest touch, the elasticity of the filaments 

 is set in motion, and their tendency to the upright position is 

 favoured. In a similar manner the filaments of the Erica 

 aggregata, (Tab. III. Fig. 13.) are bent, before they are 

 fully ripe, into a large curve, and it is by their elasticity that 

 they afterwards become erect. The same thing is observed 

 in the Hirtella^ (Tab. VII. Fig. 4.), the filaments of whicli, 

 after the antherae are ripe, become of considerable length. 



In the Euphorbiae, the filaments appear to be geniculated, 

 or as if they had a joint, (Tab. VI. Fig. 5.) But probably 

 each filament consists of two parts, the lower of which is a si- 

 milar stalk for the monandrous male blossom, as that which 

 supports the germen. According to this idea, which was first 

 advanced by R. Brown, {General Remarks on the Botany 

 of Terra Justralis, page 24.), what is commonly called the 

 corolla in the Euphorbia, is properly a common covering of 

 the flower, and incloses several male, and one female floret. 

 This idea is further confirmed by the fact, that in some species 

 of Euphorbia, we observe on the joint small laciniae or lobes, 

 which apparently are nothing else but the rudiments of the 

 interior covering, or of the proper corolla. 



The filaments of most of the syngenesious plants have also 

 a peculiarly jointed structure, as they have been represented 

 by Schkuhr, in the Cacalia, (Tab. 236.) ; and still more dis- 

 tinctly in Baccharis, (Tab. 244. Fig. h.) But, in this case, 

 the joints seem rather to occasion a shortening and drawing 

 back of the cylinder of the antherae, because, in the more ri- 

 pened state, the pistillum, with its stigma, which was before 

 included in this cylinder, rises above it. 



334. 



With respect to the structure of tlie antherae in general, 

 we find, that for the most part they resemble an extended 

 purse, surrounded by a very fine celkilar texture, wliich is 

 found throughout their whole substance, and contains, in 

 each of its cells, a small pollenous body. It is worthy of re- 

 mark, that the circumference of the antherae is not inci'cased 



