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 areole 
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 midveins (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 areole shorter, oblique 
or in costal-wing subparallel or parallel to costa, oblong, hex- 
agonal or pentagonal: midveins rarely present in lobes of segments. 
