Sensitive Fern 147 



outer areolae much shorter, mostly oblong, hexagonal or pent- 

 agonal, oblique, or those nearest parallel or subparallel, to costa. 



Venation of sporophylls pinnate, free, a simple or in forked 

 segments a once-forked veinlet occupying centre of each segment 

 of pinnules. 



Sori medial on veinlets, blackberry-shaped: sporangia nu- 

 merous, borne on a cylindrical receptacle: indusia delicate, 

 whitish, coherent at inferior side of and partly surrounding each 

 sorus, opening toward apex of segment, at first almost completely 

 covering sori, later thrown back or torn, the sporangia becoming 

 confluent. 



Spores very dark colored, ovoid. 



Habitat. Grassy banks, roadsides, the outskirts of woods 

 and thickets, low-lying meadows, etc. In damp soil exposed to 

 the sun or partly shaded. 



Range. Newfoundland to Saskatchewan, south to Nebraska, 

 Louisiana, and Florida. 



Onoclea sensibilis. Linnaeus, Species Plantarum, 1062. 1753. 



THE young plants of Onoclea sensibilis and Lorinseria areo- 

 lata are liable to be confused with each other, and before their 

 venation becomes anastomose, with Osmunda spectabilis Will- 

 denow,* but can be distinguished from the latter by the absence 

 of stipuliform appendages from the bases of the petioles, and 

 from each other by a difference in the shapes of their leaf blades. 

 The resemblance to the young plants of O. spectabilis is seen 

 only in the very first stages of development, is superficial merely, 

 and quickly disappears, but O. sensibilis and L. areolata are closely 

 related. 



*The American species better known as Osmunda regalis, but separated from the 

 European species of that name by Willdenow. 



