256 ASSISTANCE OF INSECTS IN IMPREGNATION. 



stalks soon afterwards resume their spiral figure, and 

 the fruit comes to maturity at the bottom of the water. 

 All this Micheli has described, without being aware 

 of its final purpose ; so different is it to observe and 

 to reason ! 



Some aquatic vegetables, which blossom under 

 water, seem to have a peculiar kind of glutinous pol- 

 len, destined to perform its office in that situation, as 

 Chara, Engl. Bot. t. 336, t%c. ; as well as the Fucus 

 and Conferva tribe ; but of the real nature of the fruc- 

 tification of these last we can at present only. form 

 analogical conjectures. 



The fertilization of the Fig is accomplished in a 

 striking manner by insects, as is that of the real Syca- 

 more, Ficus Sycomorus. In this genus the green fruit 

 is a hollow common calyx, or rather receptacle, lined 

 with various flowers, seldom both barren and fertile 

 in the same fig. This receptacle has only a very small 

 orifice at the summit. The seeds therefore would not 

 in general be perfected, were it not for certain minute 

 flies of the genus Cynips, continually fluttering from 

 one fig to the other all covered with pollen, and depo- 

 siting their eggs within the cavity. 



A very curious observation is recorded by Schreber 

 and Willdenow concerning the Aristolochia Clematitis, 

 EngL Bot. t. 398. The stamens and pistils of this 

 flower are inclosed in its globular base, the anthers 

 being under the stigma, and by no means commodious- 

 3y situated for conveying their pollen to it. This there- 



