612 
APPENDIX. [ Botany of Terra Australis. 
Azolla fronde circumscriptione triangular! pinnata et semibipinnata : foliolis supe- 
rioribus papulosis, radicibus longitudinaliter plumosis. Prodr. jl. nov. holt. 167- 
In lakes and ponds, frequent within the limits of the colony of Port Jackson. 
DESC. Plantula natans, facie Jungermannise. Radices axillares solitarke per- 
pendiculares byalinse, primo aspectu simplicissimse, per lentem plurnos®, novelise calyptra 
glabra subulata tectse. Frons semunctalis : Ramis distichis alternis approximatis 
parallelis teretiuscu'is 5 infimis haud rare) pinnatis ; superioribus saepe instructs gem- 
mulis ramulorum nonnullis axillaribus teretibus. Folia alterna undique imbrieata : 
in latere superiore frondis trapezoideo-ovata, crassiuscula cellulosa, viridia passim" 
rubicunda, margine exteriore submembranaceo, supra convexiuscula papuloso-scabra, 
subtus laevia : in latere injeriore tenuiora laevia, subconformia vix tamen angulata. Pcri- 
cluetxa, in superficie inferiore frondis, prope basin pinna- solitaria. 
Obs. Mr. Bauer’s very satisfactory figure and the generic character 
already given, will in a great measure supersede any farther description of 
the singular structure of this genus ; on which, however, it appears neces- 
sary 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 con- 
verted 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 membrane, 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 ceconomy of 
this part, it appears to me that as it is found in a second species of the genus, 
and of essentially the same structure, though slightly modified, the angular 
