510 Key to the System of 



SCKIZAEA. 



2136. Stalk of the fertile fronds undivided, filiform, slightly 



channelled. 



Vernation coiled-involute ; sterile fronds simple, very nar- 

 row ; stalk of the fertile frond very slender, stemlike ; 

 pinna one only, dense, short, somewhat recurved ; spore- 

 caselets in two rows, ovate-ellipsoid, their terminal ring 

 comparatively broad, transversely furrowed. 



S. fistulosa. 



Stalk of the fertile fronds once, twice or oftener 

 divided into linear rather flat segments. 



Sterile frond simple or bifid or dichotomously divided into 

 linear segments ; fertile frond with a terminal dense short 

 somewhat recurved pinna to each segment, its primary 

 stalk elongated ; spore-caselets ovate -ellipsoid, in two 

 rows, their terminal ring comparatively broad, trans- 

 versely furrowed. Figure 132. 



(S. dichotoma partly. ) S. bifida, 



GXiEXCHENXA. 



2137. Segments of the pinnas by deep division formed into 



pinnules ... 2138 



Segments of the pinnas quite undivided ... ... 213 



2138. Segments of the pinnules almost flat or somewhat 



recurved at the margin. 



Often of intricate growth, rarely dwarfed ; root (or root- 

 stock) much creeping ; stems scattered, slender ; pinnules 

 linear, developed additionally also along the short portions 

 of the ramification below each pair of the main-pinnas ; 

 segments of pinnules roundish or semi-ovate or deltoid- 

 ovate, rather firm, paler and often greyish beneath ; fruit- 

 caselets three or four, seldom more or only two, almost 

 globular, generally pale-yellowish. Figure 136. 



G. circiuata. 



Segments of the pinnules with only a small opening 

 at the lower side from broad marginal recurvature. 



Ascending to alpine elevations and there often dwarfed, also 

 particularly then beset with a brownish somewhat scaly 

 vestiture ; root much creeping ; stems scattered, slender ; 



