The Flora of the Cayuga Lake Basin 27 



/. Indusium, in local species, entire, peltate; pinnae serrate only, in local 

 species. 6. Polystichum 



d. Indusium inferior; fronds not evergreen. 

 e. Rootstocks not creeping; sori exposed. 



/. Indusium opening on one side. 2. Cystoptf.ris 



/. Indusium splitting into many stellate-spreading shreds. 



1. Woodsia 

 e. Rootstocks creeping; each sorus and its true cup-shaped indusium margined 

 or partly covered by a reflexed tooth of the frond. 7. Dennstaedtia 



1. Woodsia R. Br. 

 a. Stipe articulated a short distance above the base ; pinnae chaffy ; fronds 5-14 cm. 



high; indusium divided into slender hairs. 1. W . ilvensis 



a. Stipe not articulated; pinnae not chaffy, sparingly glandular-pubescent ;fronds 20-50 



cm. high ; indusium split into a few broad divisions. 2. IV. obtusa 



1. W. ilvensis (L.) R. Br. 



Dry exposed sandstone crests, in subacid soils; scarce. June 10-Sept. 15. 



Caroline, ledge on North Pinnacle ; Fall Creek, n. side above and below Triphammer 

 Bridge (D. in C. U. Herb.!) ; ravine between Renwick and McKinneys (A\ M. //'. 

 & A. R. Bcchtcl) ; Taughannock Gorge, n. side above the falls (A. J. E. & L. //. 

 MacDaniels). 



Lab. to Alaska, southw. to s. N. E., N. Y., Ky., and Iowa, and in the mts. to 

 N. C, including the northern Atlantic Coastal Plain. Found also in Greenland and 

 Eurasia. 



2. W. obtusa (Spreng.) Torr. 



Dry but more shaded sandstone cliffs, in calcareous or somewhat acid soils; frequent. 

 June 25-July. 



Enfield Glen, n. side, on high cliffs above the talus ; South Hill, in the " Incline " 

 cut; Fall Creek (D. in C. U. Herb.) ; McKinney Twin Glens; ravine n. of Esty, on 

 the dry cliffs of the n. side; probably elsewhere. 



Cent. Me. to Wis., southw. to Ga., Ala., Tex., and Ariz., including the northern 

 Coastal Plain; also in Alaska and B. C. 



The veinlets in both species of Woodsia emerge from the parenchyma on the 

 upper side near the tips, thus producing short linear markings which are character- 

 istic. IV. obtasa may be distinguished from Cystopteris fragilis, for which it is 

 frequently mistaken, by its less cuneate and more crenate segments, which, together 

 with the stipe, are more or less pubescent. 



2. Cystopteris Bernh. 



a. Fronds lanceolate, attenuate, often bulblet-bearing beneath ; segments and teeth 

 crowded ; rhachis not winged ; pinnules mostly oblong, obtuse at each end ; in- 

 dusium truncate on the free side. 1. C. bulbifera 



a. Fronds ovate-oblong, acute, not bulblet-bearing ; segments and teeth more distant, 

 decurrent on the slightly margined rhachis ; pinnules mostly oval, more pointed 

 and more cuneate ; indusium acute or acuminate, and often lacerate on the free 

 side. 2. C. fragilis 



1. C. bulbifera (L.) Bernh. Bladder Fern. 



Damp or wet shaded calcareous cliffs and humus, in ravines, and in the vicinity of 

 marl springs ; very common. July-Aug. 



In all the ravines of the basin, where it festoons the rocky walls ; also in swamps, 

 as s. of Caroline Depot, along Mud Creek and Beaver Brook, and on Big Gully 

 Point. 



Newf. to Man., southw. to Ga., Ala., Ark., and Iowa; rare or absent on the 

 Coastal Plain and in granitic N. E. 



