330 



THE BOOK OF CHOICE FERNS. 



or once or twice forked. Tlie spore masses, solitary or two together, are 

 terminal, and provided with an involucre (covering) that is divided nearly to 

 the base, and has round, ciliated valves. — Hooker^ Synopsis Filicum, i., p. 68. 



H. tortuosum — tor-tii-o'-sum (zigzag). Hooker and Greville. 



A pretty species, of medium growth, native of Chili, Patagonia, and the 

 neighbouring islands. Its broadly-triangular fronds, Sin. to 6in. long and 

 2in. to Sin. broad at their base, are borne on erect stalks 2in. to Sin. long, 

 of a wiry nature, and furnished on both sides with a narrow, crisped, sinuated 

 (wavy) wing, equally noticeable along the rachis (stalk of the leafy portion). 

 They are three times divided to the midrib, the ultimate divisions being long 

 and narrow, irregularly toothed, and undulated at the margin. The sori (spore 

 masses), sometimes ten to twenty to a leaflet, are stalkless and terminal on 

 the ultimate segments, and are provided with a broadly-egg-shaped involucre 

 (covering) that is divided about half-way down, the valves being slightly 

 toothed on the outer edge, — Hooker, Species Filicurn, i., p. 99. Hooker and 

 Greville, Icones Filicum, t. 129. 



H. triang"Ulare — trl-ang-ul-a'-re (triangular). Baker. 



A small-growing and prettily-divided species, native of Fernando Po, and 

 one which in habit greatly resembles H. bivalve and H. multifidum, but with 

 broader segments, and sori (spore masses) also much larger and usually 

 solitary. — Hooker, Synopsis Filicum, p. 69. 



H. tunbridgense — tun-bridg-en'-se (from Tunbridge), Smith. 



Though one of the smallest-growing, the " Tunbridge Wells Filmy Fern," 

 as this species is popularly called, is also one of the most interesting plants in 

 cultivation, and possesses additional attraction from being an eminently British 

 Hymenophyllum. It was first discovered by Mr. Dare, a botanist of the 

 seventeenth century, and was first mentioned by Petiver in his " Musei 

 Petiverani Centuria Prima," published in 1695. Mr. Petiver there calls it 

 Darea tunhridgensis minor, thus commemorating the finder and the place 

 where it was found. We find it stated in Ray's " Synopsis Methodica Stirpium 

 Britannicarum," published in 1696, that " this Fern was first shown 

 to Mr. Ray by Mr. Newton, who, in company with Mr. Lawson, found 



