THE POLYSTICHUMS 189 



habitats, since it extends far north into the Scottish glens, where 

 P. angnlare, its more delicate relative, exists but as a rare record. 

 P. aculeatum is very widely distributed, and frequents hedgebanks, 

 woods, and in the north and elsewhere is found in abundance in 

 the rocky walls of deeply cut streams, where its handsome plumes 

 of fronds may be a yard long in favoured spots. It is by no means 

 a dainty Fern, and its culture is of the easiest. Like its relatives 

 it is a thorough evergreen, and its bright, lucent fronds, see Plate, 

 do not drop, unless by stress of weather, until the new set rises in 

 the spring to take their place. In habit it is more erect than P. 

 angular e, and its most persistent differentiating character is that 

 in P. angulare the minor subdivisions have a distinct stalk, but in 

 P. aculeatum they are wedge-shaped, and the attachment is by the 

 point of the wedge, no stalk appearing. It forms a very stout caudex 

 and carries its fronds in a circle, so that a well-grown pot plant is 

 very handsome. 



This species has yielded a fair number of varieties, some, as we 

 shall see, of peculiar interest. 



Acrocladon (Fig. 214). — Found by Mrs. Thompson near Exeter ; 

 as our illustration shows, it has a very beautifully branched and 

 heavy terminal crest, the pinna? being reduced in size and tasselled 

 on regular, but smaller lines ; it is of rigid, erect habit and very 

 ornamental. 



Aculeato-cruciatum (hybridum) (Lowe). — A narrow cruciate 

 form, interesting as being, we believe, the first intentional hybrid 

 between two recognized species, viz. P. aculeatum densum X 

 P. angulare Wakeleyanum, a cruciate variety, i.e. with most of the 

 pinnae in duplicate, and set on at obtuse angles to each other, thus 

 forming crosses with the opposite pairs. Mr. E. J. Lowe effected 

 the crossing. At first the hybrid was thought to be barren, bearing 

 only aborted spores, but eventually numbers were raised showing 

 the combined characters and resembling the immediate parent. 



Acutilobum. — Found by Mr. Allchin ; subdivisions narrow and 

 acute, resembling the proliferous forms of P. angulare, and like those, 

 proliferous ; lax habit. 



Capitatum. — Heavy terminal crest. 



Corymbiferum. — Heavy bunch crest. 



Cristato-gracile. — Found by Mr. Bolton ; very spiny, small- 

 tasselled. 



Densum. — Very foliose, pinnae imbricate ; found by Mr. Jackson. 



Grandiceps Abbotts. — Found by Mrs. Abbott ; a splendid 

 form, somewhat on the lines of acrocladon. 



Pulcherrimum. — Found by a farm labourer in Dorset, and given 



