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Ameiieana. 
CLASS XX— DIOECIA. 
ORDER II. DIANDRIA. 
Sn. VALLISNERIA. JWitcheli. Gen. pi. 1491. (^Hydrocharides.) 
Masc. Spathe ovate, 2-parted. Spadix cov- 
ered with minute flowers. Calix 3-parted, 
Fem. Spathe bifid, 1 -flowered. Calix 3- 
parted, superior. Corolla of 3 petals. 
Stigmas 3, ligulate, semibifid. Capsule 
valveless, 1 -celled, seeds numerous, parie- 
tally attached. (Stamina 3 and 6.) — JSTutt. 
1. V. leaves linear and obtuse, equal from the 
base, 3-nerved, margin minutely and acule- 
ately serrulate ; male peduncles very short, fe- 
male ones spiral. — 
Jlmerican Vallisneria. Tape-grass. Channel-weed. 
Duck-grass. 
A very singular and interesting aquatic plant, hardly more, 
as Pursh correctly remarks, than a local variety of V. spiralis. 
The peduncles of the female flower are always, more or less 
spiral, particularly in deep water. Leaves three or five feet 
long, and equal in breadth all their length — little more than 
a quarter of an inch broad. In the Schuylkill, Delaware, and 
ditches below the Navy -yard, common and abundant. This 
plant grows in great abundance in the Susquehanna, and con- 
stitutes the principal food of the Anas Vallisneria of Wilson, 
(Anas ferina) or canvass-back duck; and it is said to give the 
food of that fowl its peculiar delicate flavour. Loose leaves, 
peduncles and flowers of this plant, are frequently found 
floating on the Delaware near the shores and among boats. 
Perennial. August. 
372. SALIX. Gen. pi. 1493. {Amentaceoe .) 
Masc. •Ament cylindric. Calix consisting of 
scales. Corolla uonQ. JSTectariferous glands 
