326 



THE BOOK OF CHOICE FERNS. 



A. tetraphyllum— tet-raph-yl'-lum (four-leaved), Willdenoio. 



This handsome, but very variable, stove species, also known under the 

 name of A. prionophyllum, is a native of Tropical America, where it is 

 found from Mexico and the West Indies southward to Brazil. Its massive 

 yet elegant fronds, borne on strong, upright, downy stalks rising from a 

 slowly- creeping, underground rhizome (prostrate stem), are of a very 

 peculiar shape. They consist of a long terminal pinna (leaflet) 6in. to 9in. 

 long and lin. to l|in. broad, and of numerous spreading lateral ones nearly 

 as large on both sides ; consequently, the leafy portion of the frond is 

 frequently lift, long and almost as much broad. The pinnules (leafits) are 

 of a leathery texture, jin, to fin. broad and Jin. deep, sub-dimidiate (being 

 nearly fully developed on one side of the midrib and not at all on the 

 other), their lower line straight or somewhat decurved, the upper line 

 nearly parallel, finely toothed, and the outer edge very oblique. The sori 

 (spore masses), usually of oblong form, sometimes kidney-shaped, are disposed 

 in broken lines round the upper and outer margin. — Hooker, Species Filicum, 

 ii., p. 21. Nicholson, Dictionary of Gardening, i., p. 28. 



A. t. acuminatum — ac-u'-niin-a'-tum (taper-pointed), Moore. 



The long, narrow- pointed shape of the pinna (leaflets), peculiar to this 

 garden variety, distinguishes it from the species to which it undoubtedly 

 belongs. The pale green colour of the mature foliage is remarkably pretty, 

 and the tapering termination of the fronds and of their pinnas gives the 

 plant a particularly elegant appearance. It is of similar dimensions to, 

 and has the same habit of growth as, the original A. tetraphyllum. See 

 Coloured Plate. 



A. t. gracile — grac'-il-e (slender), Moore. 



A close-growing variety, introduced from Tropical America, having 

 fronds similarly produced from an underground, slowly -creeping rhizome 

 (prostrate stem) and borne on slender black stalks of a downy nature ; 

 but these fronds are much shorter than those of the species itself, are 

 elegantly arching, bipinnate (twice divided to the midrib), and furnished 

 with numerous pinnules (leafits) of the same shape as those of the typical 

 plant but of smaller dimensions. See Plate (for which we are indebted to 



