
BRITISH FERNS 
POLYSTICHUM ANGULARE (THE SOFT PRICKLY SHIELD FERN) 
(Plate XXVIII) 
This beautiful evergreen species is closely allied to P. aculeatum, 
the Hard Shield Fern, from which it differs in its softer texture, 
more delicate cutting, and the possession of definitely stalked 
Fig. 216. 7, angulare (pinna). 
pinnules (Fig. 216), instead of wedge-shaped, stalkless ones. Al- 
though perfectly hardy, its natural habitats do not extend so far 
north as do those of P. aculeatum, and it grows with the greater 
luxuriance in our warmer western counties, and particularly in 
Ireland, while in Scotland it has been recorded in but a few of the 
lowland and western counties, the writer adding Perthshire to the 
list by finding a solitary small plant in a glen near Aberfeldy in 
association with a number of young P. aculeatums. Some botanists 
consider it to be simply a form of P. aculeatum, but no British Fern- 
grower can accept this verdict, since the two species may be found 
growing side by side in the same hedge and yet preserving their 
distinguishing characters intact. It is true that intermediate forms 
are occasionally found, but to our mind it is far more reasonable 
to impute these to accidental crosses, owing to the intermingling of 
species so closely related, or to that remarkable faculty of variation 
which this species has evinced, and as a result of which the best 
authorities have sometimes differed as to which species particular 
“sports” belonged. With these remarks we will now describe such 
varieties as are best worthy of mention, ignoring a considerable 
number which have figured in previous works, but which are now 
only recognized as sub-varieties of little or no merit. 
ACROCLADON (Fig. 217).—Found in Devon by Mr. Mapplebeck ; 
a unique form in the species, fronds branch again and again, the 
branches terminating in bunch crests. 

