516 Key to the System of 



Length and breadth of the fruit-cover about the same 2154 



2154. Fronds firm, almost rigid. 



Tall, chiefly on outskirts of forests or riparian ; fronds large, 

 pale-green or even of a slightly yellowish green, generally 

 thrice pinnate, somewhat beset with very short hairlets ; 

 pinnules upwards gradually much narrowed ; segments 

 almost semi-lanceolar, deeply lobed towards their base ; 

 cover of fruit-masses very small, also laterally open, some- 

 times partly concealed by recurvation of the nearest lobule 

 of the frond ; spore caselets on conspicuous stalklets. 

 Figure 140. (Dicksonia dubia.) D. dubia. 



Fronds tender, flaccidly membranous. 



Tall, restricted to umbrageous irrigated forest-valleys ; root- 

 stock creeping ; fronds large, dark-green, repeatedly 

 pinnate, slightly beset with hairlets ; pinnules elongate- 

 semilanceolar in outline, much narrowed into the apex, 

 their segments somewhat elliptical- or rhomboid-ovate, 

 deeply incised, rather oblique, most of the lobules slightly 

 indented, the lowest of the anterior lobules protracted ; 

 fruit-covers very small, nearly hemispherical, almost 

 exserted ; spore-caselets very minute, provided with stalk- 

 lets. (Dicksonia davallioides. ) D. dicksonioides, 



ADXANTUBX. 



2155. Densely beset with short hairlets. 



Dwarf, tufted ; vestiture slightly rough ; stalks and rhaches 

 very dark and shining ; fronds consisting of but few pinnas, 

 these dark-green, almost fascicularly crowded, all verging 

 upwards and short-stalked, very narrow in outline, the 

 outer the smallest ; segments small, often numerous, nearly 

 sessile, rather rigid, finely streaked, mostly semiorbicular- 

 rhomboid, somewhat dimidiated, bluntly denticulated 

 along the upper margin ; fruit-masses in close approach 

 to each other ; fruit-cover orbicular-renate, externally 

 prominent. A, hispiduluni. 



Glabrous or scantily beset with bristlets ... ... 2156 



2156. Frond-segments roundish-rhomboid, on conspicuous 



stalklets. 



Rather dwarf ; fronds repeatedly pinnate ; stalk and rhaches 

 very dark and shining ; segments thin, light-green, rather 

 irregularly dispersed, nearly always few only on the 

 ultimate pinnas, in front often slightly incised, at the base 

 truncate or somewhat cuneate ; fruit-cover circular- 

 renate, retracted. Figure 142. "Maidenhair-Fern." 



A. Aethiopicum. 



