138 Narrow-Leaved Chain-Fern 



lanceolate usually undulate apex: segments about eight to 

 thirteen pairs, connected by a costal-wing or below by a fine 

 ridge, oblong-lanceolate or lanceolate, largely undulate or some- 

 times sinuate, the basal narrowed at base, those above gradu- 

 ally widening, third or fourth pair usually longest: apices acute 

 or acuminate; margins serrulate, or entire in and near costal- 

 wing: rachis and midribs furnished along the sides beneath 

 and sometimes very sparingly above with small, ovate, acuminate, 

 entire or subciliate scales; midribs often brownish or olive, at 

 least when dried: surfaces otherwise glabrous, the upper deep 

 glossy green, the lower paler: texture softly membranaceous. 



Blades of sporophylls ovate-oblong, below pinnate, above 

 deeply pinnatifid, abruptly narrowing to the often lobed base 

 of the elongate linear apex: divisions narrowly linear, alternate 

 or opposite, connected by a costal- wing or ridge: apices acute, 

 margins entire in costal-wing, otherwise undulate or denticulate, 

 usually slightly revolute: rachis colored like petiole or above 

 greenish: scales small, ovate, acuminate, subciliate, borne as in 

 sterile leaves: surfaces glabrous otherwise, the upper dark green, 

 the lower paler: texture firmly membranaceous. 



Venation of sterile leaves pinnate, anastomose; marginal 

 veinlets mostly free, simple or once forked: paracostal areolae 

 elongate, parallel or subparallel to costa, those next the rachis 

 giving rise successively at ends to midribs of the segments, those 

 next the midribs to mid veins (when present), of the segments' 

 lobes; in very narrow parts of costal-wing contracted to vanish- 

 ing point or veinlets forming their outer edges alone visible, in 

 form of fibers coherent with costa: outer areolae shorter, oblique 

 or in costal-wing subparallel or parallel to costa, oblong, hex- 

 agonal or pentagonal : midveins rarely present in lobes of segments. 



