FILICES. 453 



what repand, the base truncate on the upper side, rounded on the 



lower. 



HAB. Moist woods. Can. and N. S. July. If. Fern 1218 

 inches high. Sterile fronds forming a circle with the fertile ones 

 smaller and central. Sori diverging like veins from the midrb, 

 at length confluent. 



3. A. ebeneum Willd. : frond pinnate ; pinnee sessile, lanceolate, 

 somewhat falcate, serrate, auricular on the upper side of their base ; 

 spike smooth and polished A. trichomanoides Mick. A. polypodicides 

 Swartz. Muhl. 



HAB. Rocky woods. Can. to Car. July. If. Fern 610 in- 

 ches high. Stipe brown, polished, slender and simple. Frond 

 narrow, pale green, smooth. Sori in short diverging lines, ar- 

 ranged in a double row. 



4. A. trichomanes Linn. : fronds pinnate ; pinnae roundish-oblong, 

 obtuse, crenate, the base truncate and somewhat cuneate ; stipe smooth 

 and dark coloured and A. melanocaulon Willd. 



HAB. Shady rocks. Can. to Car. July. I. A delicate fern 

 4 8 inches high. Stipe shining, blackish-purple. Frond dark 

 green. Sort linear, 5 6 to each pinnule, becoming roundish 

 when old. Distinguished from the preceding by its smaller 

 size and by having the pinnae roundish, and acute at base. 



*** Frond bipinnatifid. 



5. 'A. thdypteroides Mich. : frond pinnate ; pinnae lanceolate, sessile, 

 acuminate, pinnatifid ; segments oblong, obtuse, denticulate. 



HAB. Shady banks of streams. Can. to Car. July. If. Fern 

 1 2 feet high. Stipe smooth, not coloured. Frond ovate, fine 

 green ; pinna long, pinnatifid. Sori oblong and oblique, form- 

 ing two rows, one on each side of the partial ribs. Resembles 

 Aspidium thelypteris. 



**** Frond bipinnate. 



6. A. ruta-muraria Linn. : frond bipinnate at the base, simply so at 

 the top ; segments rhomboid- wedge-shaped, obtusely denticulate at the 

 extremity. 



HAB. Rocks. N. Y. to Car. ; not common. July. If. A 

 small fern growing in tufts, 2 4 inches high. Frond spreading, 

 rather rigid, glaucous green, bi- and tri-pinnate. Sori linear, 

 slightly oblique, at length darker and confluent. 



7. A. montanum Willd. : frond smooth, bipinnate ; pinnules oblong- 

 ovate, pinnatifid ; segments 23 toothed at the apex A. adiantum 

 nigrum Mich. 



HAB. Mountain rocks. Bethlehem, Penn. S. to Car. Schwd- 

 nitz. July. If. A fern growing in tufts, 4 8 inches high. 

 Frond having a narrow outline, mostly bipinnate ; but more 

 or less divided according to its size. Sori linear, at length con- 

 fluent. Differs from the foreign A. adiantum nigrum in being 

 much smaller, and in having the segments more obtuse. 



