38 Mr. Tuckerman, on some Plants of New England. 
| In honorem cl. inventoris, Flore Novanglicanz jam diu illus- 
j tratoris et fautoris D 
Poramoceton putcHER, (mihi): foliis omnibus petiolatis, sub- 
mersis lanceolatis natantibus ovatis oblongo-ovatisve cordatis pe- 
tiolis sepius longioribus, seminibus ventricosis lunatis dorso acute 
carinatis. P. natans, Bigel. Fl. Bost. 
Hab. Ponds and slow streams, Medford, Stoneham. With the 
floating leaves of P. natans, this species possesses the lunate and 
ventricose fruit of P. lucens and P. prelongus. From. these 
species, both of which inhabit Fresh Pond, in Cambridge, it is 
distinguished by its much larger seeds, and its beautifully cordate 
-ovate coriaceous floating leaves, often on very short peti- 
ie oles. From P. natans the structure of the fruit at once separates 
' ‘it; that of the former being not lunate, obtuse at the margins, 
abidine and finely linear-punctulate; while in ours, besides the 
difference of shape, the surface is dull and oe cca 
by elevated anastomosing veins. Conf. Koch, 
P. Cuayronu, (mihi): foliis submersis iashaonhedie amgtiite 
linearibus longis acutis margine undulatis sparsimque minutis- 
sime spinuloso-scabris versus basim vix attenuatis  sessilibus, 
natantibus petiolatis (petiolis nunc breviusculis) oblongis lanceo- 
latisve vix coriaceis (nervis non nisi versus lucem conspicuis,) 
caule ramoso.—P. foliis lanceolato-oblongis, etcett., Clayt. & 
— Gronov. Fl. Virg. edit. 2, p.23,. ex parte certe.. P. fluitans, 
 ~Pursh, Fl. 1, 120, Bigel. Fl. Bost..p. 63, Torr. Fl..1, 196. 
_ Hab. Ponds and slow streams, Roxbury, Cambridge. Very 
different from P. fluitans. From P. heterophyllus, to which ‘it 
has been latterly referred by our authors, though apparently with 
doubt by Dr. Torrey, it seems to me to differ as much as from 
P. natans. Ina large set of the European Potamogetons, I have 
not found any which agree with our plant in the peculiar features — 
of its submersed leaves. The P. heterophyllus of Pursh, col- 
lected by him at ‘ Walker’s meadows,” seems to be also the P. 
hybridus, 3. of Michaux, and to differ but little from this species. 
It may perhaps be proper to consider it a variety: §. foliis sub- 
mersis numerosioribus angustissimis. But it is possible that this 
latter plant will be found to be a distinct species. 
P.uucens, (L.) Bigel. Fl. Bost. This agrees in every re- 
spect with the foreign plant, and is easily distinguished by its 
leaves, which in P. prelongus are ovate and amplexicaul at base, 
