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OUR NATIVE SHIELD FERNS.* 



Undoubtedly there is no species of evergreen Ferns in 

 all the world which has proved itself so prolific in 

 •'mutational " or " sport " forms as two of our three species 

 of Polystichum or Shield Ferns — viz. P. angulare, or the 

 Soft Shield Fern, and P. acideatum, or the Hard Shield 

 Fern. The third species, P. louchitis, or the Holly Fern, 

 • which is only found at high levels, has not been found 

 wanting in the same direction, but has varied to so much 

 less a degree that we may ignore it in this article. Consid- 

 erable discussion has taken place — especially among foreign 

 botanists, but also among our own — as to the specific 

 distinctness of these two first-named species, but no 

 practical Fern hunter or grower can possibly feel any 

 doubt upon this point. The two species are very often 

 associated, and under precisely the same environments 

 display their distinctive characters clearly. P. aculeatumy 

 or the Hard Shield Fern, always merits the term by being 

 much harder in make and with a shining, lucent and 

 divisional character which render it unmistakable, since 

 P. angulare is of much laxer habit and of softer texture and 

 duller surface. Apart from this, there is a true specific 

 difference of make, inasmuch as while the secondary sub- 

 divisions or pinnules of P. angidave have a quite distinct 

 stalk attaching them to the rachides or secondary stalks of 

 the pinnae, those of P. aculeatum are quite stalkless, the 

 pinnules having a wedge-shaped base, by the blunt end of 

 which they are attached, no actual stalk being formed. 

 The two species also differ in the range of their habitats — 

 P. aculeatum extending far north into Scotland, where P. 

 angulare is very rare; while P. angulare is only found in 

 abundance in the South and West, and in the vicinity of 

 our warmer coasts, and also in Ireland, where P. aculeatum, 

 it is true, may also be found in comparatively small 



*By permission of the Gardeners' Chronicle. 



