SAURURACEAE 257 



pubescent, on a naked peduncle 2 to 4 inches In length, inserted opposite a leaf, on 

 one of the divisions of the stem; pedicels short, with colored, sheathing, and some- 

 what spatulate bracts, at base. 

 Jlab. Margins of pools, and streams: not common. Fl. June. JFV. Sept. 



Obs. It appears, by the correspondence of PETER COLLINSON with 

 JOHN BARTRAM, more than a century since, that this plant was then 

 known by the name of Aristolochia, probably from the resemblance 

 of its leaves to those of the Virginia Snake-root ; and that the 

 bruised rhizoma was regarded as a salutary application to sore 

 breasts, an opinion which prevails among the good ladies, who 

 deal in simples, at this day. 



ORDER LXXXVIL CERATOPHYLLA^CEAE. 



Aquatic herbs ; leaves verticillate, rather rigid, finely and dichotomously dissected, 

 without stipules ; flowers monoicous, axillary, solitary, inconspicuous, destitute of 

 calyx, but with an 8- to 12-clef t involucre. STAM. FL. Anthers sessile, indefinite 

 (12 to 20). PISTILLATE FL. Ovary 1-celled, with a single suspended ovule; style 

 filiform, oblique, persistent ; stigma simple ; fruit a beaked akene ; seed " filled by 

 a highly developed embryo with 4 cotyledons! and a conspicuous plumule." 

 A. GRAY. [" Wife 2 cotyledons and a many-leaved plumule." HOOKER & ARNOTTJ. 

 Albumen none. 



364. CERATOPHYI/L.UM, L. 



[CFr. Kerafy a horn, and Phytton, a leaf; in reference to the rigid leaves.] 

 e Generic Character the same as that of the Order. 



1. C. edlinsttum, A. Gray. Akene elliptic, with a terminal 



and 2 short lateral spines, the slightly winged margins of which 



are armed with blunt teeth that finally elongate and equal the lateral 



spines. 



C. demersum. FL Cestr. ed. 2. p. 527. not? of L. 



ECHINATE, OR PRICKLY CERATOPHYLLTJM. Horn-Wort. 



Perennial? deep green. Stem 6 to 12 or 18 inches long, filiform, branching, 

 smooth, procumbent or floating under water. Leaves in verticils of 6 or 8, half an 

 inch to near an inch long, fistular or cellular near the base, once or twice dicho- 

 tomous, the segments linear, capillary, finely serrulate, and mostly with 2 minute 

 teeth at apex. Fruit oblong, with a terminal spine formed of the indurated style, 

 and shorter spreading ones towards the base. 

 Hob, Brandy wine, Schuylkill, and their tributaries : frequent. Fl. June. Fr. Aug. 



ORDER LXXXVIII. CALLITRICHA^CEAE. 



Slender flaccid aquatic herbs; leaves opposite, entire, without stipules; flowers 

 monoicous, associated in the axils of the upper leaves, destitute of calyx, but 

 usually between a pair of small fistular whitish bracts ; stamen 1 ; anther reniform; 

 ovary 4-lobed 4-celled ; styles 2, subulate ; fruit a fleshy-membranous indehiscent 

 4 lobed 4-celled capsule ; seeds 4, solitary and suspended, filling each cell; embryo 

 in the axis of fleshy albumen. 



365. C 4I,M 'TR 1C II C. L. 



[Or. Kalos, beautiful, and Thrix, hair; from its delicate hair-like stems.] 



fgg* The Generic Character the same as that of the Order. 

 1, C. verna, L. Upper leaves spatulate-obovate, crowded and 



