[ 2 ] 



CLASS L MONANDRIA. 



ORDER II. DIGYNIA. 



1. Callitriche, L. Gen. PI. 17. (Najades.J 



Calix inferior, 2-leaved. Corolla 0. Seeds 

 4, naked, compressed. 



beterophyiia. 1. C. upper leaves spathulate-obovate ; lower ones 



linear, obtuse, and emarginated ; occasionally all 



the leaves linear. 

 C. verna. Willd. sp. pi. 1. p. 28. 

 C. aquatica. Smith, Fl. Brit. 

 C. autumnalis. Willd. sp. pi. p. 29. 

 C. linearis. Pursh, Fi. Am.'Sep. vol. i. p. 3. 



A very varying plant, putting- on at different seasons of the 

 year, such amorphous appearances, that it has been described 

 as distinct species by botanists, under the different synonyms 

 above enumerated. Dr. James Edward Smith first noticed the 

 identity of C. verna and C. autumnalis. I have adopted Pursh's 

 specific name, as it sufficiently expresses the variations in the 

 leaves ; but his C. linearis is nothing more than one of the ca- 

 pricious states of this singular plant. 



«' The leaves of the calix are described by Desfontaines as 

 being concave, and lunate, with the filament as long as the ca- 

 lix : in the American plant the stem is compressed, and bifistu- 

 lous, for floating ; the lower branches with narrower and often 

 emarginated leaves, producing only male or female flowers, 

 the central branches with retuse, spathulate oval, 3-nerved 

 leaves, bearing those which are hermaphrodite, with the sta- 

 mens much exserted." Nuttall* 



In springs, rivulets, and brooks, where the water is clear- 

 along the Schuylkill, in such places — on the bank- walk to the 

 Woodlands most abundant — in Jersey along the course of the 

 Delaware, and elsewhere. Annual. Flowers from May to 

 July. 





