igig. Praeger. — Aspleniiim Adiantiim-nignmi. 15 



at the base ; frond elongate-deltoid, very much divided ; 

 ultimate divisions linear, very acute ..." He figures (the 

 same figure appearing in the " Phytologist," 5, 36, 1854) a- 

 form quadripinnate below, tripinnate above, the lobes 

 (below) being linear-lanceolate with linear or lanceolate 

 entire acute divisions. On p. 227 he figures as a form of 

 A. Adiantum-nigrum (as opposed to A. acutum) a subquadri- 

 pinnate form, the most developed lobes being broadly 

 lanceolate and cut halfway tov/ards the midrib, the ultimate 

 lobes linear and toothed at the apex where most developed. 

 He may therefore be said to take an extreme view as to the 

 degree of subdivision which constitutes acutum. 



T. Moore, ■•■ for whose opinion Newman expresses an 

 undeserved contempt, defines var. acutum as follows : — 

 fronds deltoid, tripinnate throughout, and as well as the 

 pinnae, the lower ones especially, caudate ; ultimate pinnules 

 narrow-lanceolate, inciso-pinnatifid, the lobes linear, very 

 acute, entire. He adds that the larger fronds are almost 

 quadripinnate. The plate shows a well developed tripinnate 

 frond with the lobes ovate and cut about half way to the 

 midrib, the teeth being linear, and bidentate at the tips ; 

 also a group of fronds of a much less developed form, scarcely 

 even tripinnate, and though markedly caudate at the 

 apices, not worthy of reference to Bory's acutum. 



Hooker^ is very moderate in his requirements as to the 

 characters which constitute the variety : — " pinnae pinnules 

 and segments narrower often linear acute or acuminate." 

 His figure in the latter work represents a form scarcely 

 tripinnate, the pinnules ovate-elongate, the lobes lanceolate 

 toothed at the apex. A more rigorous diagnosis appears in 

 the later editions of Hooker and Arnott's " British Flora ": — 

 " lower pinnae triangular-acuminate bipinnate, ultimate 

 segments linear very acute " ; but this is again toned down 

 in Hooker's " Student's Flora " to "lower pinnae triangular- 

 acuminate, segments narrow very acute " — thus eliminating 



^ " The Ferns of Great Britain and Ireland . . . Nature Printed." 

 Plate xxxvii. and letterpress thereto, 1855. 



2 " Species Filicum," 3, 188, i860 ; and " The British Ferns," plate 33, 

 1861, 



A 2 



