126 DESCRIPTIONS OF N.Z. I<ERNS. 



however, I am quite certain that it is only a form of A. umbrosum ; as in their early 

 stages it is quite impossible to distinguish between plants of it and of van parvifolium. 

 I have a slightly crested form of it. It is very easily cultivated in sandy soil, mixed 

 with leaf-mould ; as, indeed, are all the forms of A. umbrosum. They all die down in 

 winter, and re-appear in spring ; so that probably they would not survive the frosts of 

 the Middle Island, unless under shelter. 



Another Asplenium, of the sub-genus Diplazium, was found by Mr. Cheeseman, 

 at the Kermadecs, about two years ago, but is not known to occur in New Zealand. 



TRIBE ASPIDI.E. (As-pid-e-£e.) 



"SHIELD FERNS." 



So called from aspis, a shield, because the involucre is round and covers the 

 sorus. The botanical definition includes the following characteristics, Sori dorsal, 

 sub-globose, rarely elliptical. Involucres superior, similar in shape to sori, and fixed 

 by the centre or by a sinus. 



GENUS ASPIDIUM. (As-pid-e-um.) 

 Has the sori sub-globose, dorsal, terminal on veinlets. Involucres orbicular, 

 fixed by the centre. All the N. Z. Aspidia belong to the 



SUB-GENUS POLYSTICHUM. (Po*l-ist-ik-um ) 

 Which has the veins all free ; texture coriaceous ; and teeth awned, that is having 

 a sort of thorn or claw at the point. 



ASPIDIUM ACULEATUM. (As-pid-e-um a-cu-le-a-tum.) 



"PRICKLY SHIELD FERN." 

 PLATE VIII., No. 2. 



Rhizome stout, hard, erect, sometimes forming a caudex two feet to five feet 

 high, and bearing a handsome crown of fronds. Stipes variable in length, stout, 

 ibrown or grey, and more or less thickly covered with large dark scales. Rachis the 

 :same, and often clothed with hairs also. Fronds sometimes three feet long, oblong, 

 long-oval^ or lanceolate, bipinnate. Pinnae and pinnules many and stalked : the latter 

 very broadly lanceolate, almost rhomboidal, and rather deeply and sharply toothed. 

 Texture coriaceous ; colour usually dark olive-green. Sori numerous and near to 

 costae. Involucres round and flat. The above may be called a general description ; 

 but the fern varies so greatly in different localities, and even in the same neighbour- 

 hood, that it would be impossible to specify all the forms, from their passing into each 

 other by imperceptible gradations. The New Zealand fern is what is generally classed 

 as " Var. vestitum ;" but I lately saw in the " Waterfalls Gully," near Dunedin, plants 



