BOTANY OP TERRA AUSTRALIS. 53 



different texture; in all these respects it approaches to 

 Cvperaceae, with some of Avhose genera it has even a cer- 

 tain resemblance in habit. This genus has usually been 

 found only within the tropics, but in New Holland it 

 extends as far as 33° S. lat. 



P/iilydrum, which I have annexed to Junceee, has always 

 appeared to me an insulated genus, yet though not re- 

 ferable to any established natural order, it may be com- 

 pared Avith several in certain respects. In the structure of 

 its stamina it may in one point of view be said to be in- 

 termediate between Scitaminese and Orchideae ; in that of 

 its pericarpium and even of its seeds it has some affinity to 

 the latter order ; yet it differs from both of them in almost 

 every other respect. In general appearance, it bears a 

 considerable resemblance to Cartoneiua, which belongs to 

 Commelinese. In some parts of its structure it may be 

 compared with Xyris, and perhaps with Burraannia; a 

 genus which I have likewise annexed to Juncese, but whose 

 real affinities are equally obscure. 



PJiilydrum pygnicsum differs in so many respects from 

 P. lanuginosimi that it may probably hereafter be con- 

 sidered as a distinct genus ; and a very few additions to 

 this tribe of plants would sanction their formation into a 

 separate natural order. 



RESTIACEiE. The principal character distinguish- [579 

 ing this family from Juncese and Cyperaceas consists in its 

 lenticular embryo being placed at the extremity of the 

 seed opposite to the umbilicus ; from Juncese it also differs 

 in the order of suppression of its stamina, which when re- 

 duced to three are opposite to the inner laciniffi of the 

 perianthium; and most of its genera are distinguishable 

 from both these orders as well as from CommelineEe by 

 their simple or unilocular antherss. 



With the exception of Eriocaulon, Tonina, and Xyris, 

 the order appears to be confined to the Southern hemi- 

 sphere. In Terra Australis its maximum is in the princi- 

 pal parallel, but it extends to the southern extremity of 

 Van Diemen's Island, where it is even *m considerable 



