CLASS XXIV. ORDER I. 419 



tifid, segments oblong, obtuse, entire, ciliate ; fruit 



marginal ; stipe smooth. 



Syn. PoLYPODiUM Noveboracense. L. 



About the middle size, smooth and even, with obtuse segments, 

 mostly entire. — Roxbury, Bussey's hill. — Perennial. 



AspiDiuM Thelypteris. Sm. Meadow Shield Fern. 



Frond pinnate, its divisions pinnatifid, subcrenate, 

 distinct at base, decussating; dots of fructification 

 confluent. ySni. 



Common in low, moist grounds, about the edges of meadows 

 and swamps. Stipe glabrous. Divisions of the frond long and 

 slender, the lower pairs frequently decussating, or crossing each 

 other; a circumstance which Dr. Smith has noticed in his spe- 

 cific character. They are pinnatifid, or deeply cut into oblong, 

 roundish segments, which are slightly crenate at the edge, and 

 revolute when in fruit. The first segments of each division are 

 at a little distance from the stipe, and seem to form a parallel 

 line on each side of it, running through the whole length of the 

 frond, a character well represented in the figure of Plukenet. 

 The fruit commences in small dots, and finally overruns the 

 whole under surface of the frond. — Perennial. 



AspiDiuM Lancastriense. Muhl. 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 MARGixALE. Sic. Marginal SMcld Fern. 



Frond pinnate, its divisions subpinnate, glabrous, 

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

 dots marginal. 



Syn. POLYFODITJM MARGINALE. L. 



NePHRODIUM MARGINALE. Midi. 



A larger fern than either of the preceding. Stipe chaflfy. Di- 



