414 NEW HEPATIC^. 



27. Riccia, Linn. 



1. R. plana, Tayl. ; fronde orbiculari, cavernosa, stellatim 

 4-5 lobata ; lobis planis, quadrato-rotundatis, crenatis, sub- 

 tus nudis. 



Hab. Swan River. Mr. James Drummond. 



Fronds scarcely \ an inch in diameter, and the lobes about 

 3 lines, greenish-white, slightly crenate or irregularly angu- 

 late ; when moistened the cavernous appearance vanishes ; 

 margins of the lobes scarcely elevated. This has some resem- 

 blance to R. crystallina, L. : — however, the fronds are more 

 thin and delicate, wider, more angulate, by no means chan- 

 nelled and more compressed to the soil. 



2. R. acuminata, Tayl. ; fronde orbiculari, radiatim divisa ; 

 lobis linearibus, dichotomis, acuminatis canaliculatis, mar- 

 gine elevato, inflexo, subtus nudis. 



Hab. Swan River. Mr. James Drummond. 



Fronds 1 inch in diameter. When moistened, the lobes 

 swell and their margins are so closely inflexed as to remind 

 one of the lirellce of an Opegrapha. The under surface is 

 quite destitute of scales. The pale green frond looks as if 

 sprinkled with a white powder. The acuminate lobes distin- 

 guish this species from R. crystallina, L. 



3. R. cancellata, Tayl. ; fronde suborbiculari, cavernosa, ra- 

 diatim divisa, lobis incrassatis, excavatis, dichotomis lineari- 

 oblongis, obtusis, margine subtus nudis. 



Hab. Swan River. Mr. James Drummond. 



Lobes nearly 2 inches long, of a sordid, pale green colour, 

 very tumid, the cavernose depressions varying in size but 

 crowded. This is one of the largest species of the genus. 

 In a dry state there is a brown tinge of the base of the 

 lobes. 



4. R, vesicata, Tayl. ; fronde cuneata, dichotoma, lobis ap- 

 proximatis, linearibus, obtusis, tumidis, subcanaliculatjs, 

 corrugatis, vesiculates, margine subtus nudis, tubiferis. 



