432 CILICES. [AlsopTiila. 



the Hills of Sikldm. A glauca, J. Sm. ; Clarke 432 ( A. contaminans, Wall. ; Kurz 

 ii. 573 ; Gamble 88) Vern. PaJcjik, paludum, Lepcha, is a splendid tree fern of the 

 lower hills of Sikkim, Eastern Bengal and Burma. It is probably the largest Indian 

 species, reaching a height of 50 feet, with a stem of considerable girth at tlie base, 

 smaller above but widening again beneath the fronds. These fronds are very large, 

 often reaching 10 to 12 feet in length, and the fern is easily recognized by its smooth 

 rachis and leaves glaucous beneath. A. ornata, J. Scott, Clarke 432, and A. 

 Andersoni, J. Scott, Clarke 433, are Sikkim species, which are very rare and but little 

 known. They were collected first by the late Mr. Scott, in the Cinchona plantation 

 at Rangbi, at an elevation of 2,500 feet. A. Oldhami, Bedd. ; Clarke 433 (A. 

 Scottiana, Baker ; Gamble 88) is a very pretty tree fern, not uncommon about 

 Parjeeling, and usually gregarious and branching. A.fflabra, Hook. ; Clarke 433 ; 

 Kurz ii. 573 ; Gamble 88, is the common species of the plains. It is found in damp 

 forests in the Sub-Himalayan tract and Eastern Bengal, from Nepal down to Chittagong 

 and Tenasserim, Central and Southern India, and Ceylon (A. gigantea, Hook. ; Thw. 

 Enum. 396). It is, however, rather a small species, rarely reaching to more than 15 

 feet, though Clarke says it occasionally attains 50 feet. A. crinita, Hook., is a tree 

 fern of South India and Ceylon reaching 20 feet in height and remarkable for its 

 being densely covered with shaggy scales. None of these species are used in India, 

 except that the inner part of the stems of Sikkim species is sometimes eaten by Lepchas. 



Brainea insignis, Hook. ; Kurz ii. 574 ; Clarke 571, is a tree fern of the pine forests 

 of the Martaban Hills, at 4,000 to 6,000 feet elevation. It has a stem only 3 to 5 

 feet high. 



Among other species of ferns, which, though not exactly arborescent, are yet re- 

 markable and of interest in the Indian forests, may be mentioned Anyiopteris evecta, 

 Hoffrn., a thick fleshy fern of most of the moister regions of India, with a huge fleshy 

 root-stock and leaves which often reach 6 feet in length. Acrostichum aureum, Linn. 

 Vern. DheJcwa, Beng. is a handsome fern, used occasionally for thatching in the 

 Sundarbans. On the hillsides and in the forests of most of the mountainous regions 

 of India is found the Bracken, Pteris equilina, Linn. Aspleniumpolypodioides, Mett 

 is a common large-leaved fern of the Himalaya, which has ofteii'a distinct stem of a 

 few feet in height, and may almost be ranked as a tree fern. 



The structure of the stems of tree ferns presents a great difference from 

 that of either Dicotyledonous or Monocotyledonous trees. The appear- 

 ance of the stem is usually that of a dark brown cylinder, marked above 

 by regular scars, the bases of fallen leaves, and below by an entangled 

 mass of fibres formed by the interlacement of roots. The inner structure 

 is shewn by a horizontal section to consist mainly of three portions: 

 First, the outer layer formed by the bases of fallen leaves and interlacing 

 rootlets ; secondly., the cellular tissue which occupies the greater part of 

 the interior; and, thirdly, the vascular bundles which form an irregular 

 and cylindrically arranged ring inside the cortical layer. These vascular 

 bundles present the appearance of a closed mass of curved, usually cres- 

 cent-shaped, outline, having on the outside a hard black layer of woody 

 fibres, and inside two light-coloured layers of soft tissue, chiefly contain- 

 ing scalariform vessels. When dry, the cellular tissue which fills the 

 interior contracts, leaving usually a hollow space, the rin<? of vascular 

 bundles then showing a wavy pattern of alternately light and dark 

 layers. 



