88 GENERAL REMARKS ON THE BOTANY OF TERRA AUSTRALIS. 



supersede any farther description of the singular structure 

 of this genus ; on which, however, it appears necessary to 

 subjoin a few remarks. 



Admitting the parts of fructification to be accurately 

 described, it is not easy to understand in what manner the 

 male influence is communicated to the female organ. In 

 one instance the turbid fluid, which usually fills the cavity 

 of the lower cell of the supposed male organ, was found 

 converted into a powder, and it is not improbable that this 

 change ultimately takes place in all cases where the organ 

 attains perfection. This powder may be supposed either 

 to be discharged by the lateral rupture of the double coat 

 of the containing cell, or a communication may at length 

 be opened between this cell and the tubular axis of the 

 upper cell, which, after the separation of its outer mem- 

 brane, is open at the top ; in this case the ejection of the 

 pollen, or even of a fluid matter, may possibly be aided by the 

 pressure or action of the angular solid bodies which sur- 

 round this axis, and its dispersion would, no doubt, be 

 assisted by the increased surface of its divided apex. 



But whatever supposition may be formed respecting the 

 economy of this part, it appears to me that as it is found 

 in a second species of the genus, and of essentially the same 

 613] structure, though slightly modified, the angular bodies ot 

 the upper cell being only six in number, there can remain 

 little doubt of its being really the male organ. 



The genus Azolla was founded by Lamarck on speci- 

 mens of the South American species entirely destitute of 

 fructification, the remains of which only appear to have 

 been seen more recently by Willdenow^ who describes it as 

 " a Capsula unilocularis polysperma." 



KEFERENCES TO TAB. 10. 



Azolla pinnata. 



1, riaut of the natural size, 



2. — mamiificd. 



