FILICES. (FERNS.) 667 



# Fronds bipinnate. 



11. A. acilleatum, Swartz, var. Braunii, Koch. Frond spreading 

 (l-2 long), oblong-lanceolate in outline, with a tapering base, the lower of 

 the many pairs of oblong-lanceolate pinnae gradually reduced in size and obtuse ; 

 pinnules ovate or oblong, obtuse, truncate and almost rectangular at the base, 

 short-stalked, or the upper confluent, sharply toothed, beset with long and soft 

 as well as chaffy hairs. (A. Braunii, Spenner.) Deep woods, mountains of 

 New Hampshire, Vermont, N. New York, and northward. (Eu.) 



13. CYSTOPTERIS, Bernhardi. BLADDER-FERN. (PL 18.) 



Fruit-dots roundish, borne on the back of a straight fork of the free veins ; 

 the delicate indusium hood-like or arched, attached by a broad base on the inner 

 side (towards the midrib) partly under the fruit-dot, early opening free at the 

 other side, which looks toward the apex of the lobe, and is somewhat jagged, 

 soon thrown back or withering away. Tufted Ferns with slender and delicate 

 twice or thrice pinnate fronds ; the lobes cut-toothed. (Name composed of KUOTIS, 

 a bladder, and Tire pis, fern, from the inflated indusium.) 



1. C. blllbifera, Bernh. Frond lanceolate, elongated (l-2 long), 

 2-pinnate; the pinnae lanceolate-oblong, pointed, horizontal (l'-2'long); the 

 rhachis and pinnae often bearing bulblets underneath, wingless; pinnules crowded, 

 oblong, obtuse, toothed or pinnatifid; indusium short, truncate on the free side. 

 ( Aspidium bulbiferum, Swartz. A. atomarium, Mull. !) Shaded ravines, 

 &c. : common. July. 



2. C. fragilis, Bernh. Frond oblong-lanceolate (4' -8' long, besides the 

 stalk which is fully as long), 2 -3-pinnate ; the pinnae and pinnules ovate or lan- 

 ceolate in outline, irregularly pinnatifid or cut-toothed, mostly acute, decurrent 

 on the margined or winged rhachis ; indusium tapering or acute at the free end. 

 Var. DENTATA, Hook., is narrower and less divided, barely twice pinnate, with 

 ovate obtuse and bluntly-toothed pinnules. (Aspidium tenue, Swartz. } Shaded 

 cliffs : common, and very variable. July. (Eu.) 



14. STRTJTHIOPTERIS, Willd. OSTRICH-FERN. (PL 15.) 



Fruit-dots round, on the pinnae of a separate contracted and rigid frond, the 

 margins of which are rolled backward so as to form a somewhat necklace-shaped 

 or continuous hollow body enclosing the fruit : there are 3-5 pinnate free veinlets 

 from each primary vein, each bearing a fruit-dot on its middle : fruit-dots crowded 

 and confluent ; the sporangia borne on an elevated receptacle which is half-encir- 

 cled at its base by a very delicate semicircular and ragged evanescent indusium. 

 Sterile fronds large, very much exceeding the fertile, pinnate, the pinnae 

 pinnatifid, all growing in a close circular tuft from thick and scaly matted 

 rootstocks. Stipes stout, angular. Pinnate veins free and simple. (Name 

 compounded of arpovdos, an ostrich, and irrepis, a fern, from the plume-like 

 arrangement of the divisions of the fertile frond.) 



1. S. Germanica, Willd. Sterile fronds smooth, broadly lanceolate, the 

 lowest pinnae gradually much smaller ; pinnae very numerous, narrowly lance- 

 olate, deeply pinnatifid ; the lobes oblong, obtuse : fertile frond with somewhat 



