AUSTRALIAN FERNS. 69 



tuber osum (NepJirolepis) , found at the Teviot, Brisbane, Clarence 

 and Macleay Elvers; and A. decomposition (Neplirodiuvri) ranging 

 from Cape Otway to Eockinghain Bay, and collected at Penola 

 by the Eev. J. E. Woods. 



The last mentioned species is a very variable one, and sometimes 

 occurring without indusia. Dr. F. Mueller mentions two lead- 

 ing varieties, A. marginans and A. tenerwm. The specimens of A. 

 tenericaule (NepJirodiwin) forwarded to me by Mr. Macgillivray 

 resemble some forms of Hypolepis or Polypodium, as they appear 

 without indusium (for which Mr. Macgillivray assures me he 

 searched in vain), but there can be no hesitation in saying that 

 the plant in question is the same as that figured in the fourth 

 volume of the Species Filicwn, the involucre or indusium there 

 being represented as obsolete. Hooker, however, states that 

 sometimes it has a very small indusium of a cordate reniform 

 shape and membranaceous. This fact should lead pteridophilists 

 to be cautious in determining species without comparing speci- 

 mens from different localities, for it really seems in this instance, 

 that the fern which in some places looks like a Hypolepis or Poly- 

 podium, occurs in others as a true Neplirodium. Much difficulty 

 respecting the varieties of Polypodium rugosulum and Hypolepis 

 dicksonioides, has arisen from, want of properly estimating the ex- 

 indusiate forms of Neplir odium. 



SUB-ORDER 9. Polypodies. 



This extensive suborder includes those ferns which have not 

 any involucre or indusium, but naked sori of a round or oblong 

 shape. The genus Polypodium is so called because some of the 

 species ha^e a multitude of roots which form close entangled 

 patches, the word being a compound of poly " many," and pous, 

 podos, "a foot." According to Sir "W. Hooker, Polypodium com- 

 prises Campyloneuron, Grammitis, Arthropteris, and some other 

 so called genera, as that distinguished author preferred arranging 

 them in separate sections under one great genus, rather than 

 maintaining as independent genera several groups of plants which 

 have " no tangible character." In the genus Polypodium the 

 veins are either free or netted, and the species differ very much 

 in size, structure, and habit. Without dwelling upon the various 

 subdivisions of the genus, it may be sufficient for my present 

 purpose to remark, that the Australian species may be con- 



