KEYS TO THE FERNS OF BORNEO 
323 
b 1. Veins free or indusium naked. 
c. Pinnules articulate to rachis, sori 
terminal on veins 37. Didymochlaena. 
a. Pinnules not articulate, sori dorsal on 
veins. 
d. Sorus double, the halves facing each 
other, indusium opening where the 
halves meet 47. Phyliitis. 
di. Sorus simple (borne by a single vein). 
e. Paleae thin, not black, roots not 
stout and black, sori confined to 
one side of vein 46, Asplenium. 
ei. Paleae usually harsh and dark, 
roots usually black and stout, 
lowest sori usually bent across 
vein, or on both sides of vein 45. Athyrium [part). 
H. DICKSONIEzE, and DAVALLIEzE in part. 
Sori marginal or nearly so, with an indusium opening on the marginal side, 
not protected by a veflexed margin. 
a. Pinnae articulate to rachis. 
b. Terrestrial, small ferns 5. Schizoloma [part). 
&i. Epiphytes, middle-sized 29. Nephvolepis (part), 
a 1. Pinnae not articulate to rachis. 
b. Veins confluent in the sori. 
c. Decompound with cuneate ultimate 
pinnules 27. Odontosoria. 
ci. Ultimate pinnules not cuneate. 
d. Marginal sorus continuous 5. Schizoloma (part), 
di. Sorus interrupted 26. Lindsay a (part), 
bi. Each sorus at the end of a single vein. 
c. Fronds under 40 cm. long 26. Lindsaya (part), 
ci. Fronds over 60 cm. long. 
d. Rhizome creeping, fronds scattered 2. Dennstcedtia. 
di. Rhizome erect, fronds clustered. 
e. Pinnules oblique at base 18. Balantium. 
ei. Pinnules not very oblique at base. 
/. Not glaucous 28. Cystodium. 
fi. Glaucous beneath, annulus com¬ 
plete X- Cibotium, 
I. PTERIDEiE. 
Sori marginal, protected by the reflexed margin. 
a. Fronds dimorphous, annulus complete 50. Plagiogyria. 
ai. Fronds uniform, linear and entire 71. Vittaria (part), 
at. Fronds uniform, not simple and entire. 
b. Sporangia borne on the inner face of the 
reflexed margin 12. Adiantnm. 
bi. Sporangia not borne on reflexed margin. 
