AUST11ALIAN TEENS 55 



but in these cases there is a difference of habit which seems to 

 determine their proper place in the suborder. With regard to 

 P. nudiuscula (Brown's Pteris nudiuscula), so little is known, that 

 Hooker hesitated whether to refer it to Pellcea or Noihochlasna. 

 It seems probable that it belongs to the latter genus, for in many 

 respects it resembles the forms of Notliocldcena, to which we shall 

 have occasion to refer by and by. As Pteris is a large genus, 

 and, generally speaking, easy to be recognised, it may be useful 

 to state that any ferns which have the fructification marginal, 

 linear and continuous, with a narrow involucre somewhat mem- 

 branaceous, may be referred to the same group. The veins are 

 generally very distinct, but varying in shape, being sometimes 

 reticulated, so that the species may be conveniently arranged in 

 separate sections according to the venation. The species best 

 known in Australia are P. umlrosa, P. tremula, P. aquilina, (for- 

 merly P. esculenta), and P. incisa (formerly P. vespertilionis, or 

 the bat's wing). P. aquilina is one of our commonest ferns, and 

 according to Hooker, is a mere variety of the European species, 

 or rather of that widely distributed fern, which in one or other of 

 its forms is found in both hemispheres, in almost all the tropical 

 and temperate parts of the world. Our fern is of a rigid or co- 

 riaceous texture, and it was originally called " esculent," be- 

 cause it was regarded as identical with the edible fern of the 

 South Sea Islanders. Dr. Clarke, F.L.S. has lately brought to 

 light the esculent properties of the European variety, and there- 

 by has afforded another proof of its intimate alliance with that of 

 the south. P. umbrosa, P. tremula, and P. incisa, are very grace- 

 ful and ornamental ferns. P. pedata is a small plant common to 

 Tropical Australia and many parts of the West Indies, as well as 

 South America. 



Ccratoptcris tfidlictroides is an interesting aquatic fern, floating 

 or attached to soil in shallow waters. It was found by Cunning- 

 ham in Groulburn Islands, and also by Dr. F. Mueller, in North- 

 West Australia, &c. Hooker remarks that it is entirely sui 

 generis, as it differs from all others in so many respects that 

 botanists cannot agree to the exact place it should occupy. 



Having reviewed the Australian Pteridece, as known to Sir W. 

 Hooker, I shall now turn to the same order as recently inves- 

 tigated by Dr. E. Mueller, that some idea may be formed of the 



