i * 
228 EB. Tuckerman on New England Planis. 
Pate we 
terophyllus, notices a Potamogeton from North Carolina, as pos 
sibly a distinct species, which seems from his description to be the 
present. P. Acronis Americani, Nuttallu, provisionally thus 
disposed by Chamisso, (Linnea, 2. p. 226, & t, VI, f. 25,) accords 
also in every respect with P. Claytonii, except the described and ri 
figured orbiculation of the fruit, the base of the nutlets inour ~ gi 
plants being always, so far as I tenve observed, acutish, and the ‘ 
whole outline consequently obovate. The specimen without fruit, 
from North Carolina; described on the next page of the same me- 
moir, as well as probably that from Pennsylvania, described at 
the same place, also belong, neha without doubt, to P. Claytonii. . , 
P. heterophyllus, Pursh, Fl. 2, p. 120, which is included in 
that part of Pursh’s Herbarium that j is in my possession, isa plant 
resembling Claytonii, but much smaller and more delicate 
throughout, explaining thus the citation in the Flora of P. hy- 
bridus, Michx., as a synonym of so different a species as the P. 
heterophyllus of authors. . It was noticed as variety @ in my for- 
mer account of the present species, in this Journal, with the re- 
mark that it might turn out to be distinct. The stem is extreme- 
ly slender, branched, and apparently. much compressed, about a 
foot long ; the submersed leaves: elofigated, very narrow-linear, 
acuminate, sessile, 3-nerved, 4-4 a line wide and 3-5 inches Jong ; 
the floating ones ( sometimes undistinguishable from the others, 
or the blade a little widened below the acuminate tip, and the rest 
of the leaf serving as a“petiole) papyraceous, very delicate, — 
ceolate, with about 10 impressed nerves: - oo under side, the 
largest about an inch and a quarter long, by about five lines in 
width, on elongated, compressed petioles ; Sashes slender, very 
long, nerved.- ‘Ihe leaves are approximated, with something of 
a fasciculate aspect. It is found,saccording to Pursh’s Flora, in 
slow flowing waters of Virginia and _—— and his ticket, (up- 
on which “ P, hybridus” seems to have been writt and 
+“P. heterophylias” afterwards nddedl rena the 
ker’s meadows.” The P. hybridus of Barton’s Comper 
x 
inppeoritl take thename of P. Purshii 
P. Spirillus, (Sp. nov.) : caule compresso, ~~ ‘akan con- 
cavo-convexo, ramoso ; foliis submersis membranaceis gramineis 
cum stipulis connatis basique vaginantibus linearibus obtusis 
3-nerviis sessilibus; natantibus subeoriaceis oblongis lanceolatis 
linearibusve, subtus nervis 3-7 impressis’sulcatis, petiolis canali- _ 
culatis cum stipulis infra medium connatis ; ; Stipulis folioruam sub- — 
~ mersorum liguliformibus hyalinis laceratis ; spicis partis submerse 
alaribus capitatis ‘paucifloris brevissime: pedunculatis Foret 
lis erectiusculis compressis’clavatis, natantis cylindricis plur 
longius pedunculatis; fructibus recentibus obovato-lenti 
