KEYS TO THE FERNS OF BORNEO 
319 
c. Indusium fixed at a point 
a. Indusium fixed by the base, or base 
and sides 
c2. Indusium fixed by the whole margin 
bz. Sori elongate on veins, with indusia 
& 3 . Sporangia in marginal, or nearly marginal 
sori, indusiate. 
b. Indusium free on side facing margin 
bi. Indusium formed by reflexed margin 
D. “ Aspidiese.” 
E Da vallie se 
(Part). 
F. Cyatheese and 
Woodsiese. 
G Aspleniese. 
H. Dicksonieaeand 
Da vallieae 
(Part). 
I. Pteridese. 
A. “ ACROSTICHEzE.” 
Sporangia not gathered into sori, covering the back of the frond or parts of it. 
a. Sporangia confined to an elongate apical 
segment of the entire frond ; epiphytes 63. 
a*. Sporangia on the back of simple entire 
frond. 
b. Frond coriaceous or pubescent; epiphytes 64. 
b 1. Frond thinner, glabrous; mostly terres¬ 
trial. 
c. Rhizome creeping 43. 
ci. Rhizome suberect 41. 
a 2. Fertile frond lanceolate, entire, sterile 
frond broad and forked ; terrestrial 54. 
a 3 . Sterile green fronds repeatedly forked ; 
nest-buildings epiphytes 55. 
a\. Frond typically pinnatifid or pinnate. 
b. Fronds dimorphous as a whole. 
c. Rhizome high-scandent. 
d. Veins free unless near costa 48. 
di. Veins everywhere anastomosing 44. 
£i. Rhizome creeping or short-scandent 43. 
c2. Rhizome erect; terrestrial. 
d. Veins anastomosing everywhere 41. 
di. Veins anastomosing near costae 42. 
dz. Veins free 39. 
in. Sporangia on apical segments or pinnae. 
c. Sterile part of frond pinnatifid, 
epiphytes 67. 
ri. Frond pinnate throughout. 
d. Fertile pinnae linear; usually 
epiphytic 69. 
4 *. Fertile pinnae broader; terrestrial 
in brackish marshes 56. 
Hymenolepis. 
ElapJioglossum. 
J^eptochilus (part). 
Hemigramma (part). 
Cheiropleuria . 
PI aty cerium. 
Stenoclilcena. 
Loma gramma. 
Leptochilns (part). 
Hemigramma (part). 
Stenosemia. 
Polybotrya. 
Merinthosorus. 
Photinopteris. 
A crostichuni. 
