392 Class XXIV. Order I. 



A great difference, in appearance, exists between the barren 

 and fertile fronds of this plant. The barren frond is composed 

 of large, broad, oblong, sinuated leaves or divisions, the lower 

 ones distinct, the upper ones connected by their base. The fer- 

 tile frond is much narrower, its divisions short, its segments 

 nearly globular, enclosing the fruit, and forming a sort of raceme. 

 Low grounds. Perennial. 



450. STRUTHIOPTER-IS. 

 STRUTHIOPTERIS PENNSYLVANIA. Willd. Ostrich Fern. 



Barren fronds twice pinnate ; segments entire, ob- 

 tuse, the lowest elongated, acute. 



Syn. ONOCLEA NODULOSA. Schkuhr. 



One of our largest native ferns. Stipe of the barren frond re- 

 markably channelled or hollowed out in front. Divisions of the 

 frond pinnatifid, the segments curved forward and subacute, those 

 next the stipe curved backward, falcate and acute. Fertile 

 frond a sixth part as large, composed of a multitude of dense, 

 turgid, brownish segments, the edges recurved, and the back 

 covered with fruit. Low grounds, Hanover, New Hampshire. 



451. ASPLENIUM. 

 ASPLENIUM RHIZOPHYLLUM. L. Walking Leaf. 



Frond lanceolate, stipitate, subcrenate, auriculate- 

 cordate at base, the point very long, linear, rooting. 



A curious fern, striking root at the extremity of the frond, 

 from which root new plants arise. In rocky woods in the west- 

 ern parts of the state. 



ASPLENIUM TRICHOMANES. MX. Dwarf Spleenwort. 



Frond pinnate ; divisions roundish, crenate, wedge 

 shaped at base. 



Syn. JISPLKNIUM MELANOCAULON. Mtlhl. 



An extremely small and delicate fern. Frond pinnate. Stipe 

 smooth, of a shining black colour. Divisions or leafets sessile, 

 nearly round, crenate upon their outer edge, entire and acute 

 at base. Fructification in about five or six linear, diverging 



