770 FERNS Ol' NORTH gPKKVSl.ANM) 



Tho rharartrr of the stem, tlie nniglinoss or smootlinrss of the 

 stipes, and tlie nature of tlie scales at the Uase of tlie stipes, are 

 indispensable factors in tlie (ieterniination of species. The stem 

 of A. nuitfrnfis is always densely covered with the distinctly muri- 

 cate bases of the old fronds: the scales at the base of the stipes 

 are of one kind only, though varvini; miicli in size; they are of a 

 rich br(»wn colour, shininij, stitlish, more or less appressed, fr<im 

 a broad base ijradnally narnnved and en«lin<^ in a very fine 

 prickle-point, entire throughout, or with a margin of hyaline 

 cilia, sometimes sli<?htly serrulate below the jiricklc point ; more 

 over, tho stipites are comparatively slender. A. excehn nud A. 

 Coope.ri show numerous clean scars on the stem, where the old 

 fronds have fallen completely away; the stipes is much more 

 robust; and the scales are of two kinds, a larger and a smaller, 

 l)oth of them serrate throughout. The dilVerences between A. 

 excelsn and A. Cooper i are not so sharply d(;Hned. The former 

 is much more robust in its growth and attains a much greater 

 height; it is coarser and more coriaceous in the texture of its 

 fronds; the base of tlu^ stipes is distinctly muricate, while that 

 of A. Cooper i is almost smooth; the scales at the Iwise of the 

 stipes also show distinctive characters; the larger scales of A. 

 Cooperi attain a length of 2" and are of a smoky-white colour, 

 while those of A. exceJsa are much shorter and are light brown 

 in colour; in l>oth species, the smaller scales are reddish-brown 

 and serrated, but, in A.e.rcefsa, the serrations appear to be stronger 

 and more closely set than in A. Coojh'vi. The nerves, in A. 

 excefsa, are deeply embedded in the more coria(*eous substance of 

 the pinnules, while, in A. Cooperi, they are generally distinctly 

 visible; the pinnules, too, are wider, with strongly recurved 

 margins. Moreover, the spores of ^4. Conprri are more papillose 

 than those of A. rxcr/sa. Domin follows C Moore in regarding 

 A. Cooperi as a var. of A. frcf/sa; but, after careful examination 

 of specimens of both ferns in the Botanic Gardens, Sydney, 1 

 prefer to keep them distinct. Moreover, T incline to the opinion 

 that the typical A. exceha is limited to Norft)lk Island, and that 

 the Australian plant, throughout, is A. Cooperi. More extended 

 observations are, however, necessary, especially on Norfolk Island 



