174 122 



Subgenus 7. CvcloSOrUS (Link) C. Chr. 

 Biolog. Arbejder tilegnede Eug. Warming pag. 81. 1911. 



The American species ol' this subgenus are all biiiiniiatifid and closely related 

 to each other. The rhizome is erect or creephig, ch)thed with lanceolate or ovate, 

 as a rule hairy and entire scales. Lamina with a broad i)ase or shortly narrowed 

 downwards. Aërophore none; under -surface often glandular, especially on the 

 ribs. Most species rather pubescent by simple, unicellular hairs, only in some few 

 species the longest hairs consist of 2 — 3 cells, or some of the hairs of the rachis 

 are forked from the very base if. inst. in certain forms of D. oligophylla). In some 

 species rachis and the costæ beneath bear some few minute, lanceolate scales, 

 which often bear long hairs along the edges. Veins simple, the basal ones either 

 connivent to sinus, where they meet or more often are separated by a cartilagineous 

 membrane that can protrude between the segments as a projecting apophysis, or 

 truly united in the leaf-tissue and sending a branch to the sinus. Sori often large, 

 indusiate. Indusium reniform, generally persistent and pilose, often also glandular. 

 Sporangia glabrous (Ü. Martini excepted, which see). 



Cyclosorus is allied to Lastrea and Steiiopteris. Its best characters are venation, 

 non-decrescent lamina and large, persistent indusia. In America it is represented 

 by a dozen species, most of which are very variable and connected by inter- 

 mediate foi-ms. The subgenus is as a whole the most dilficult to deal with and 

 several of the species can be distinguished from each other by certain characters, 

 which can not be explained by words or figures but which are easily observed by 

 the trained eye. Two of the species, D. mollis and 0. yongylodes, are not exclusively 

 American but widely distributed in the Old-World, where the subgenus is richly 

 developed. 



Key. 



Lamina pinnate only, see D. pusilla nr. 54 under ,>!> Lastrea. 

 Lamina bipinnatifid : 

 Basal tertiary veins free or connivent to sinus, not normally united 

 in the leaf-tissue. 

 2. Rhizome erect. Rachis not scaly. 



;i Basal scales broad, thin, yellowish or brown, as a rule glabrous. 

 Lower pinnæ not reduced. Basal segments both prolongated 



and parallel to rachis 190. D. patens (Sw.). 



3. Basal scales narrow-acuminate, ferruginous, glossy, hairy. Lower 

 pinnae somewhat reduced. Basal segments (at least the posterior 

 one) not conspicuously prolongated. 

 4. Pinnæ 4--6 cm long by 1 cm broad, lathcr liriii. 191. I), (ioidenii Wos. 



