420 



THE BOOK OF CHOICE FERNS. 



handsome species presents a peculiarity of special note, inasmuch as, instead 

 of the frond being fertile throughout, the spores are almost exclusively 

 confined to the upper portion, where the sori (spore masses) are disposed 

 in parallel lines, situated nearer the midrib than the edge, and form, so to 

 speak, two rows of circles gradually diminishing in size from the base of 

 the pinna? to their point on each side of the mid vein. — Hooker, Species 

 Filicum, iv., p. 18. Nicholson, Dictionary of Gardening, i., p. 126. Lowe, 

 Our Native Ferns, i., t. 20. Eaton, Ferns of North America, ii., t. 62. 

 Bedalome, Ferns of Southern India, t. 121. 



A. aculeatum has produced comparatively few striking varieties, although 

 in a list published in March, 1865, by Mr. P. Neill Fraser, of Canonmills 



Lodge, Edinburgh, we find that no less 

 than twenty-three of them are enumerated. 

 But this was at a time when British Ferns 

 were at the height of their popularity, and 

 it is doubtful if half that quantity have 

 survived, and could now be found in 

 collections. 



A. a. acrocladon — ac-roc'-lad-on 

 (branched at the summit), Lowe. 

 This remarkably handsome form, which 

 was originally found in the neighbourhood 

 of Exeter, is undoubtedly the most ex- 

 quisite of the several crested, forked, or 

 branched forms of A. aculeatum known. 

 The greater portion of the fronds, 

 ,.,„„,. ,„,.,. , which attain l^ft. in length and are 



tig. 59. Frond of Aspidium aculeatum acrocladon ° 



(much reduced), of a rich green colour, is narrow. They 



are furnished with pinna? (leaflets) which, 

 on their lower portion, are again divided to the midrib, while the upper 

 portion is dilated and slightly crested. The summit of the fronds is three- 

 branched : the branches again forking, and their branches forking again, form 

 a head of dense, multifid (many-cleft) segments (Fig. 59) sometimes three 

 times, the width of the lower portion of the frond. In general appearance, this 



