262 OF TUE. VALISNEKIA. 



circumstance for our purpose is the closing of the flow- 

 ers at night, which is sufiiciently well established. 



But the most memorable of aquatic plants is the Falis- 

 neria spi?'alis, well figured and described by Micheli, 

 Abu. Gen. t. 10, which grows at the bottoms of ditches 

 in Italy. In this the fertile flowers stand on long spiral 

 stalks, and these by uncoiling elevate them to the surface 

 of the water, where the calyx expands in the open air. 

 In the mean while plenty of barren flowers are produced 

 on a distinct root, on short straight stalks, from vvhich 

 they rise like little separate white bubbles, suddenly ex- 

 panding when they reach the surflice, and floating 

 about it in such abundance as to cover it entirely. Thus 

 their pollen is scattered over the stigmas of the first- 

 mentioned blossoms, whose stalks soon afterwards re- 

 sume their spiral figure, and the fruit comes to maturity 

 at the bottom of the water. All this Micheli has de- 

 scribed, without being aware of its final purpose ; so dif- 

 ferent is it to observe and to reason ! 



Some aquatic vegetables, which blossom under water, 

 seem to have a peculiar kind of glutinous pollen, des- 

 tined to perform its oflice in that situation, as Char a ^ 

 Engl. Bot. t. 336, &c. ; as well as the Fuciis and Cow- 

 ferva tribe : but of the real nature of the fructification 

 of these last we can at present only form analogical con- 

 jectures. 



The fertilization of the Fig is accomplished in a strik- 

 ing manner by insects, as is that of the real Sycamore, 

 Ficus Sycomorus. In this genus the green fruit is a hol- 

 low common calyx, or rather receptacle, lined with va- 

 rious flowers seldom both barren and fertile in the same 



