84 32 



towards the sinus but not meeting there and thus not being truly connivent; costulæ 

 run out from the costæ under open angles. Sori indusiate or not, the indusium 

 rarely large and persistent. Sporangia glabrous. 



Ctenitis is a very natural group, by the peculiar pubescence different from all 

 other groups of the genus, and I have no doubt that the differences are of generic 

 value. The species vary being from bipinnate to decompound, most of them with 

 characteristic obtuse segments, rather small to large. All intermediates between 

 bipinnate and large decompound species are found, such are f. inst D. slrigilosa 

 and Ü. Hemsleyana. In America the bipinnate species are numerous in Southern 

 Brazil, while only one, Ü. vellea, occurs in the West Indies, where several decom- 

 pound species {D. hirta, D. ampla, D. nemorosa etc.) are to be found. In the Old 

 World's tropics the subgenus is fairly well represented. Among them is the African 

 D. cirrhosa (Schum.) O. Ktze., which I cannot distinguish specifically from the 

 Brazilian D. eriocaulis (Fée) O. Ktze., a new example of the well-known relation 

 between the floras of South Brazil and tropical West Africa. 



Ctenitis is not nearly related to the other subgenera of Dryopteris and in my 

 opinion it is even not congeneric with them. On the other hand it is intimately 

 related to the genus Psomiocarpa Presl., recently restored by Christ'), who referred 

 to that genus two West Indian species, Ps. aspidioides (Griseb. ) and Ps. Maxoni 

 Christ. I know the first named of these species, which in habit, texture, colour 

 and pubescence is perfectly agreeing with Ctenitis; by its contracted fertile frond 

 it differs, however, so much that it naturally must be placed in a separate genus, 

 which can be regarded as a derivate of Ctenitis. Psomiocarpa was previously 

 united with Polybotrya, which genus is more closely related to Polystichum. 



Ctenitis is further related to the genus Aspidium (Tectaria) at least to the 

 majority of the species referred to that genus. The main diflerence is found in 

 the venation, Ctenitis having free veins, Aspidium reticulated veins; in pubescence, 

 texture and colour most species of the two genera fully agree. Species intermediate 

 between the two genera exist, f. inst. Dryopteris Rrauniana (Karst.) O. Ktze. from 

 Colombia (Kaksten; Lindig nr. 261 (B); Lehmann (RB)). It has free veins but is 

 in habit rather a species of Aspidium, to which genus I refer it, wherefore it is 

 not included in this paper. 



In the following I deal with 24 species. It is, in this subgenus, impossible 

 lo draw a sharp line between the bipinnatifid and the more divided species. Some 

 of the species vary considerably in cutting being bipinnatifid, bipinnate or tri- 

 pinnatifid. I have chosen to include in this monograjjh those species only of which 

 I have had type-specimens and which in the most developed form are scarcely 

 more than bipinnate. 



The 24 species can be divided into smaller groups, which are connected by 

 intermediate characters: 



') On Psomiocarpa, a neglected genu.s of ferns. Smitlisoniaii Misc. Colleclions ÖO nr. 'I'i. 1911. 



