REPORT OF THE STATE BOTANIST, I919 65 



NYMPHOIDES (Tourn.) Hill 



There are three species in the eastern United States, one of which 

 is introduced, known under the common name of floating heart. 

 They have had quite a varied nomenclatorial career. Formerly 

 placed in the genus V i 1 1 a r s i a , they have since been transferred 

 tirst to Limnanthernum, and more recently to N y m - 

 p h o i d e s . 



The type of Nymphoides, is N . f 1 a v a Hill, which is the 

 M e n y a n t h e s n y m p h a e o i d e s Linn. (Nymphoides 

 p e 1 1 a t u m ( S. P. Gmel. ) Britten & Rendle ; Nymphoides 

 nymphaeoides (L.) Britton). This with two or three closely 

 related species of the Old World is characterized by having terminal 

 flowers in sessile umbels, or the umbels in the forks of the upper 

 leaves, the segments of the corolla ciliated and seeds with a fringelike 

 margin. It is clearly not congeneric with the native species of the 

 eastern United States, and the generic name Nymphoides, should be 

 restricted to ,N. nymphaeoides (L.) Britton, said to be natural- 

 ized in ponds in the District of Columbia, and to those species of the 

 Old World possessing the same general characters. Among other 

 generic names applied to this type are : Limnanthus Necker 

 (1790), Limnanthes Stokes (1812), Waldschmidia 

 Weber (1780) and Schweyckerta C. C. Gmelin (1805). 



TRACHYSPERMA Raf. Med. Repos. (II) 5:352. 1808. 

 Villarsia J. F. Gmelin, Syst. 447. 1791. Not Villarsia Neck 1790. 



The native species of floating heart of the eastern United States 

 are characterized chiefly by the flower umbels being attached to the 

 petioles of the usually floating leaves, and accompanied by tufts 

 of rootlike tubers, the seeds smooth or glandular roughened and the 

 white corolla-lobes entire. 



The type species is designated by Rafinesque as Trachy- 

 s per ma natans (Menyanthes trach}'sperma 



Michx.). 



Trachysperma aquatica (Walt.) comb. nov. 



Anonym OS aquatica Walt. Fl. Car. 109. 1788. 

 Villarsia aquatica J. F. Gmel.. 1. c. 



Menyanthes trachysperma Michx. Fl. Bor. Am., 1:126. 1803. 

 Trachysperma natans Ra f ., 1. c. 



Limnanthernum trachyspermum A. Gray, Man. Ed. 5, 390. 1867. 

 L. aquaticum Britton, Trans. N. Y. Acad. Sci., 9: 12. 1889. 

 Nymphoides aquaticum Kuntze, Rev. Gen. PI. 429. 1891. — Fernald, 

 Rhodora, 10:55. ^908. 



