MARSILEACEvE. 471 



2. SALVINIA. MichelL Salvinia. 

 (In honor of Salvini, an Italian professor.; 



Reproductive organs near the root solitary, or in racemes of 

 3 5, covered with brown rigid hairs. Upper ones of each ra- 

 ceme filled with innumerable spherical bodies, brownish and 

 reticulated ; lower ones more oblong, containing 6 18 larger 

 oblong-ovoid, brown and reticulated bodies, on short stout com- 

 pound pedicels. (Griffith, in Lind. Veg. King.) 



S. natans Willd. : leaves elliptic, subcordate, obtuse, with fascicles ot 

 hairs above. Marsilca natans Linn. 



Lakes and still waters. Can. and Western N. Y. Pursh. Leaves opposite, 

 2-ranked, fine green. Floating on water like a Lemna. Floating Salvtnia. 



3. ISOETES. Linn. Q,uill-Wort. 



(From the Greek t^os, equal, and eroj, the year, or evergreen.) 



Spore-cases membranaceous, oblong, 1 -celled, not opening, 

 imbedded in the dilated base of the frond. Spores globose or 

 slightly angular, attached to numerous filiform receptacles which 

 traverse the capsule. 



/. riparia Engelman : emersed rhizoma small (orbicular ?) ; leaves slen- 

 der, soft, yellowish-green ; sheaths short (longer than broad) ; spores neatly 

 and minutely farinaceous and reticulated. (Sill. Jour. Jan. 1847.) 



In ponds and wet shady places. Banks of the Delaware below Philadelphia. 

 Chester county, Penn. Darlington. July, Aug. 1L|.. Root or rhizoma 4 or 5 

 lines in diameter. Fronds numerous, 46 inches long, (Engelm.), 4 12 or 15 

 inches, (Darlingt.}, linear subulate, somewhat like the leaves of a Juncus. 

 Fructification oval-oblong, membranaceous, imbedded in the swollen base of the 

 frond. According to Professor Brauri, I. lacustris has hitherto been found only 

 in middle and northern Europe. See Sill. Jour. Jan. 1847. 



Mud Quill-wort. 



