162 110 



membrane between them ; this membrane is in leaves of thick texture often folded 

 and forms on the underside an often hairy keel running from the sinus towards 

 the costa and parallel to the costules. Indusium in most species large, reniform, 

 as a rule persistent. Sporangia glabrous. 



A natural group including 13 known species of middle-size or large-grown 

 and partly closely related to each other. The majority of them resemble in habit 

 not a little D. rudis and allied species, in venation, indusium and rhizome D. oli- 

 gophglla: the subgenus thus connects the two groups of which the two species na- 

 med are typical members. From both it can be distinguished by the characteristic 

 carinate fold below the sinus, the grey colour and the pluricellular hairs. From 

 the free-veined species of Goniopteris all species are different by the lack of stellate 

 hairs. Glands are absent in all species. 



The two last species, D. glandulosa and D. Fendleri, are somewhat different 

 from the others. Their position in this subgenus is doubtful ; see below. 



Key. 



1. Pinnæ sessile or the lower ones very shortly stalked. All veins free. 

 2. Lamina pinnatifid (or pinnate below only) with entire segments 



177. D. Wrightii (Mett.) O. Ktze. 

 2. Lamina bipinnatifid. 



3. Lower pinnæ more or less reduced. 



4. Lamina suddenly narrowed downwards with several pairs of 



auriculiform, reflexed pinnæ 178. D. deltoidea (Sw.) O. Ktze. 



4. Lower pinnæ abbreviated but not auriculiform. 



5. Lamina membranous-papyraceous, pinnæ incised to a narrow wing 



to costa 179. D. L' Herminieri (Kze.) C. Chr. 



5. Lamina rigidly coriaceous; pinnæ incised about halfway 



to the costa 180. D. lonchodes (Eat.) O. Ktze. 



3. Lower pinnæ not reduced, generally reflexed. 

 4. Without aërophore. Lamina rather thin. 



5. Rachis and costæ beneath with many short hairs with 

 some few long, pluricellular hairs intermixed. Pinnæ 

 incised to a wing 3 — 5 mm broad; veins 9— 10-jugate 



181. D. densiloba C. Chr. 

 5. Rachis, margins, costæ and veins beneath with many 

 very long, pluricellular hairs, short hairs few. Pinnæ 

 incised nearly to costa; veins 10 — 11-jugate 



182. D. incana (Christ) C. Chr. 

 4. Aërophore present. Lamina firm, membranous or papyra- 

 ceous. 

 5. Fronds dimorphous. Stipe and rachis very densely clothed 



