298 THE CANADIAN NATURALIST. [Aug. 



diameter; leaves ovate obtuse, rounded and roughened on the 



back (Eaton). Resembles a floating moss or Jungermannia 



(Torrey). Grray, Man. Bot., t. 14. Floating on the waters of 



Lake Ontario, Pursh Fl. Am. Sept., ed. 2, ii, p. 672. In the 



adjoining states. Professor Asa G-ray notices it as occurring in 



pools and lakes, New York to Illinois and southward, and observes 



that it is probably the same as A. magellanica of all South 



America. 



Salvinia. 



\_S'dvinia natans, = Marsllea nutans, Linn. Sp. pi. '' Floating 

 like Lemna on the surface of stagnant waters, in several of the 

 small lakes in the western parts of New York and Canada." — 

 Pursh Fl. Amer. Sept. ed. 2, ii, p. 672. Professor Asa Gray states, 

 that it has not been found by any one except Pursh, and he there- 

 fore omits it from his Manual of Botany of the Northern States.] 



ISOETES. 



/. lacusfris, L.— Beloeil, C. E., P. W. Maclagan, M.D. ; Sas- 

 katchewan, Hook. Fl. Bor. Amer. This plant is spoken of by 

 Pursh as growing in the Oswego River, near the Falls ; and Pro- 

 fessor Gray and others allude to it as not rare in the New England 

 States. It should be carefully looked for in the numerous lakes 

 and creeks of Upper Canada. It grows in muddy bottoms, form- 

 ins green meadows under water. Much interest is attached to 

 the genus Isoetes, since Professor Babington has shown tha 

 instead of one there are many species, or at least distinct races or 

 forms, in Britain. In the United States four are known : — 

 /. laciisfris, Linn.; /. riparia, Engelm.; /. Engelmani, Braun ; 

 and I.flaccida, Shuttlew., the last a southern form. Professor 

 Babington is certain of the existence of at least eight European 

 species : — /. laciistris, L. ; /. echinospora, Dur. ; /. tenuissimaj 

 Bor. ; I. adspersa, A. Br. ; /. setacea, Del. ; /. velata, Bory. ; 

 /. Hystrix, Dur. ; and /. Duricei, Bory. As yet we know of 

 only one Canadian species, which is here rendered, rather uncer- 

 tainly, /. lacustris. The American species are described in 

 Gray's Manual, the British ones in the new Journal of Botany, 



London. 



JVat. Ord. EQUISETACEiE. 



Equisetum. 



The Equiseta having been described in a previous paper, it 

 will be sufficient to give here a mere list of the species, with some 

 additional notes obtained since the former paper was written. 



