74 A CONTRIBUTION TO, ETC. 



the Blue Mountains, and other places not too much exposed to 

 the salt air. Mr. Macgillivray has recently noticed some forms 

 of these plants on the Eichmond, and he evidently regarded them 

 as distinct species, the one being uniformly a more coriaceous 

 plant than the other. Hooker's P. querdfoliiim is a tropical 

 species, and distinguished by having the sterile fronds variously 

 lobed often half-way to the midrib. The fertile frond is pinnatifid 

 with the segments oblong acuminate, and the sori are small and 

 numerous. The allied species P. diversifoliwn of the same author 

 was collected on the Blue Mountains by Miss Atkinson, and in 

 tropical Australia by others. Sir W. Hooker regards Willdenow's 

 plant as a variety of P. scandens, but Brown does not intimate 

 that his P. diversifolium is allied to the scandent species. As 

 the country to the north becomes opened up, and favourable lo- 

 calities are carefully examined by intelligent observers, these 

 ferns will be better known, and we shall be able to form a correct 

 opinion as to the protean appearances of the climbing Polypodia. 

 Dr. F. Mueller has recently expressed an opinion that many of 

 the forms, formerly regarded as distinct species, may be more 

 properly considered mere varieties ; and if Sir William Hooker 

 had been spared to complete his great work, he had intended to 

 publish a " Synopsis Filicum," with a view of omitting all 

 dubious ferns, and of checking what he considered " the unneces- 

 sary multiplication of species." P. proliferum, which has some- 

 times been referred to Neplirodium, has recently been found at 

 the Eichmond Eiver by Mr. Macgillivray. The fronds are gla- 

 brous, somewhat coriaceous, and pinnated, being repeatedly pro- 

 liferous at the apices and axils of the pinnae, and they are gene- 

 rally about two feet long, with pinnae from three to six inches 

 long. The veins sometimes connive and form a continued vein or 

 costule, as in Nephrodium unitum. P. verrucosum has also been 

 found at Eockingham Bay, and seems to be identical with the 

 species occurring at Penang, Singapore, &c, It is a distinct and 

 handsome species. 



SUB-ORDER 10. Grammitidece. 



Next to the genus Potypodium, Sir William Hooker describes 

 the suborder Grammitidece, which includes several genera with 

 sori more or less oblong or linear, and destitute of any involucre. 

 " The Grammitideos are distinguished by the generally very elong- 



