316 Tl.'ANKACTlONS AND PROCEEDINGS OF THE [Sess. LXVII. 



so-called lohahvm-genuinum and aculeaturii." ?>. Mr. Wm. 

 Stewart, Glasgow, has no belief in lohatum as a sub-species, 

 and considers it only a form of aculeatum. 4. Mr. Robert 

 Kidston, F.R.S., who informs me that " a specimen of 

 lohatum, under cultivation, eventually assumed the typical 

 form of aculeatum, though the change in assuming the 

 typical form of aculeatum took some years to accomplish." 

 From all this it would seem that lohatum is but an early 

 state of aculeatum. 



Of the three acknowledged British species, then, of 

 PolysticJmm, we take first P. Loncliitis, looked on as the 

 type of the genus, and occurring in all four divisions of 

 the Kingdom. It is a mountain rock-plant, — rather 

 almost an arctic species, for it is found in the high 

 latitudes of Europe, Asia, and America, and also in the 

 Himalayas. It ranges on the Breadalbaues up to o400 

 feet, and is found most frequently nestling below large 

 boulders. It is the most hardy British fern, and an 

 evergreen. Its main characteristic is that its numerous 

 and sometimes overlapping pinnce are not divided into 

 pinnules. In its mature state, this, which we know as 

 the Holly Shield-fern, is not confoundable with either of 

 the other two. 



Regarding P. aculeatum and F. angulare, though these, 

 when normally grown, are sufficiently distinct from one 

 another, they are occasionally somewhat closely alike, and 

 liable to confuse even the experienced eye. Various 

 points of distinction may be touched off as follows, viz.: — 



1. aculeatum is more glossy in appearance, and more 



rigid in texture ; 

 angulare is more lax and drooping, and the teeth 

 of the leaves being long-awned, the whole plant 

 is softer in appearance and to the touch. 



2. aculeatum has its pinnules wedge-shaped, i.e. shaped 



like an acute angle at their base or point of 

 attachment, and they are almost sessile, i.e. they 

 can hardly be described as stalked ; 

 in angulare, on the other hand, the base of the 

 pinnules is in the form almost of a right angle, 

 and the pinnules are distinctly stalked, so dis- 

 tinctly. Dr. Thomas Scott remarks, that when 



