Sect. Cyathea
Indusium an entire cup with even edge at maturity of sorus, if fragile sometimes breaking later
. . . . . . . . . . C. orientalis
Indusium otherwise or lacking
Indusium at maturity an almost flat disc, in some cases hidden by mature sorus, in some cases the residual part of a complete indusium of which the thin apical parts fall away at maturity
Indusium at maturity a disc with fairly even edge
. . . . . . . . . . C. javanica
Indusium at first covering sorus, apical part very thin and caducous, an irregular disc remaining on old sorus
. . . . . . . . . . C. crenulata
Indusium otherwise or lacking
Indusium entirely brown and rather firm, quite covering sorus to maturity, breaking only when old
. . . . . . . . . . C. oinops
Indusium in part pale and fragile, breaking at maturity, or not entirely covering sorus
Bullate scales present (if at all) towards apex of costa; costal scales few; pinnules to 100 mm. long
. . . . . . . . . . C. junghuhniana
Bullate scales abundant to base of costae and on costules; pinnules to 65 mm. long
. . . . . . . . . . C. raciborskii
Sect. Gymnosphaera
Pinnules almost entire
. . . . . . . . . . C. glabra
Pinnules distinctly lobed
Scales on lower surface of costules bullate
. . . . . . . . . . C. lurida
Scales on lower surface of costules not bullate
Scales on costae bearing lateral setae; segments or lobes of pinnules rounded and subentire; sori usually not converging towards apices of segments; basal basiscopic vein from costule
Stipe and basal part of rachis persistently scaly; largest pinnules with stalks at most 2 mm; veins to 6 pairs
. . . . . . . . . . C. subdubia
Persistent large scales only at base of stipe; largest pinnules with stalks to 4 mm; veins 3-5 pairs
. . . . . . . . . . C. glabra
Scales on costae lacking lateral setae; segments of lamina deltoid and distinctly toothed; sori converging towards apices of segments; basal basiscopic vein often from costa
. . . . . . . . . . C. gigantea
Subsect. Sphaeropteris
Scales on costules abundant, copiously fringed with long crisped hairs which become entangled and form a woolly covering
. . . . . . . . . . C. tomentosa
Scales on costules not thus fringed
Stipe conspicuously spiny; pale hairs on lower surface of costae few or lacking
. . . . . . . . . . C. tenggerensis
Stipe warty; pale hairs abundant on lower surface of distal half of costae and on costules
. . . . . . . . . . C. persquamulifera
Subsect. Fourniera
. . . . . . . . . . C. tripinnata
Subsect. Schizocaena
. . . . . . . . . . C. squamulata
