364 



THE BOOK OF CHOICE FERNS. 



A. nigra — nig'-ra (black), Martins. 



This stove species, native of Rio Negro, Brazil, is one of the most 

 distinct, and one of the easiest to identify, among all the known South 

 American Alsophilas. Its ample fronds, of a peculiarly deep green colour, 

 slightly hairy on all the ribs and rarely showing a few scales on their under- 

 side, are borne on rather slender, ebony-black spiny stipes (stalks). The 

 principal rachis (stalk of the leafy portion of the frond) is also ebony- 

 black, and the pinnas (leaflets), 12in. to 14in. long and 4in. to 5in. 

 broad, are furnished with oblong pinnules (leafits) 2jin. long, ^in. broad, 

 and divided two -thirds of the way down to their midrib : the lobes thus 

 formed are oblong, bluntish, and notched at their edges. The sori (spore 

 masses) are disposed half-way between the midrib and the margin of the 

 fertile lobes. — Hooker, Species Filicum, i., p. 45. 



A. nitens — nit'-ens (bright). Synonymous with A. aspera. 



A. nOYae-caledonise — nov'-re-cabe-don'-i-as (native of New Caledonia), 

 Mettenius. 



A stove species, from New Caledonia. Mettenius compares it with 

 A. truncata of Brackenridge, which, no doubt, is the nearest species, but from 

 which it is, however, perfectly distinct. The fronds are tripinnate (three 

 times divided to the midrib), of a leathery texture, glossy as if A^arnished, and 

 wholly covered underneath with fructification ; they are borne on stipes 

 (stalks) of the same rough nature as the rachis (stalk of the leafy portion 

 of the frond). Their primary pinna? (principal leaflets), ljft. long and 6in. 

 broad, are furnished with secondary ones that are sessile (stalkless), very 

 narrow -oblong, Jin. broad, and pinnate (cut down to their midrib), except 

 at their long, tapering summit, where they are toothed like a saw. The 

 pinnules (leafits) thus formed are two and a-half lines long, less than one 

 line broad, bluntish and stalkless, their recurved margins being furnished 

 with small, roundish teeth. The copious small sori (spore masses) occupy 

 the whole of the space between the midrib and the margin of the fertile 

 pinnules. — Hooker, Synopsis Filicum, p. 39. 



A. oblonga — ob-lon'-ga (oblong), Klotzsch. 



In this stove species, native of British Guiana, the fronds, ample and 

 tripinnatifid (three times divided half-way to the midrib), have spear-shaped 



