Class XXIV. Order I. 391 



ASPIDIUM LANCASTRIENSE. MM. Lancaster Shield Fern. 

 Frond pinnate ; divisions nearly opposite ; segments 

 triangular-ovate, acutely serrate ; stipe naked. 



Rather long and narrow. Fructification chiefly confined to the 

 upper divisions, and in large, blackish dots. Wet meadows, West 

 Cambridge. Perennial. 



ASPIDIUM MARGINALE. Sw. Marginal Shield Fern. 



Frond pinnate, its divisions subpinnate, glabrous, 

 with oblong, entire lobes, sinuate-repand at the base ; 

 dots marginal. 



Syn. POLTPODIUM MARGINJILE. L. 



NEPHRODIUM MARGINALE, Mich. 



A larger fern than either of the preceding. Stipe chaffy. 

 Divisions of the frond nearly pinnate. Subdivisions or segments 

 distinct, oblong, obtuse, crenatc, contracted at base, afterward 

 decurrent, so that their common stalk becomes slightly winged, 

 or the division pinnatifid. Dots of fructification distinct, round, 

 close to the margin. Their umbilicated involucre is very obvi- 

 ous. Woods, Roxbury. Perennial. 



ASPIDIUM ASPLENIOIDES. Muhl. Dark Shield Fern. 



Stipe glabrous ; frond twice pinnate ; segments ob- 

 long, cut toothed ; dots reniform, arranged near the 

 nerve. 



This is a large, smooth, brittle fern. Divisions of the frond 

 pinnate ; the segments oblong, acute, with distinct teeth, separ- 

 ated by deep indentations. The teeth are again denticulate, 

 and the lower ones somewhat obtuse. Fructification with re- 

 niform or lunulate involucres, at first resembling lines, as in 

 Asplenium, afterwards extending over the whole under surface 

 of the frond, giving it a brownish appearance. Moist woods. 



449. ONOCLEA. 

 ONOCLEA SENSIBILIS. L. Sensitive Fern. 



Barren fronds pinnate ; segments cut, the upper 

 ones united ; fertile fronds doubly pinnate, with re- 

 curved, globular subdivisions. 



