448 ACOTYLEDONOUS PLANTS. 



*** Frond tematf, bipinnate. 



4. P. dryopteris Linn. : frond ternate, bipinnate, spreading and de- 

 flexed ; segments obtuse, somewhat crenate ; sori marginal j root 

 filiform, creeping. 



HAB. Hanover, N. H. Big. Arc. Amer. ; rare. July. H- 

 Fern a foot high. Root black, creeping and slender. >'/// 

 slender, smooth and erect. Frond drooping, tender and of a 

 light green colour. Often confounded with the next, from 

 wnich it is distinct. 



5. P. calcarcum Smith : frond ternate, bipinnate, erect, rather 

 rigid ; segments somewhat obtuse, subentire ; sori marginal, conflu- 

 ent Nephrodium dryopteris Mich. 



HAB. Wet shady grounds. Can. to Penn. July. If. Differs 



from the preceding in its more rigid habit, its somewhat duller 



green and paler confluent sori, as was fust shown by Sir J. E. 



Smith. Mr. Charles S. Parker, of Liverpool, a very accurate 



, botanist, informs me that P. dryopteris and calcareum are found 



in one locality, near Matlock, (Eng.) and that they preserve 



their distinct characters in cultivation. 



2. ONOCLEA. Linn. 



Capsules covering the whole lower surface of the frond. In- 

 volucre formed of the frond turned inwards, resembling a 

 berry, opening but not expanding. 



1. O. scnsibilis Linn. : sterile fronds pinnate ; pinnae lanceolate, 

 acute, laciniate, upper ones united ; fertile fronds bipinnate, resem- 

 bling a compound spike, with recurved globular segments ; rachis 

 smooth. 



HAB. Moist woods. Can. to Flor. July. II. Fronds several, 

 1218 inches high, with a long and smooth stipe ; the fertile 

 ones very narrow. 



2. O. obtusilobata Scltk. : sterile fronds pinnate ; pinnse opposite, 

 pinnatifid ; segments rounded, lower ones gradually smaller, upper 

 ones united ; fertile fronds bipinnate ; pinnules incised, recurved-glo- 

 bose, villose; stipe scaly. O.sensibilis var. obtusilobata Torr. 



HAB. Low grounds. Penn. Pursh. N. Car. Sclnce'mitz. July. 

 If. Smaller than the preceding, and has the pinna opposite, 

 with rounded segments. Mr. Schweinitz considers it quite dis- 

 tinct. 



3. ASPIDIUM. SWrfe. 



Sori roundish or elliptical, scattered. Involucre roundish 

 or kidney-shaped, umbilicated or opening on one side. 



* Frond pinnate. 



1. A. acrostichoides Willd. : frond pinnate ; pinnae lanceolate, fal- 

 cate, acute, ciliate-serrate. auricled at the upper angle of their base, 



