3 20 
natans f 
fluitans. 
heteropkyl- 
lum. 
setaceum . 
perfoliatum. 
lucens . 
TETRANDRIA TETRAGYNIA. 
154. POTAMOGETON. Gen. pl. 234. 
1. P. foliis longe petiolatis natantibus sublanceolato-ovali» 
bus, primariis nonnullis subcordatis. Midi. jl. amer. 1. 
p. 101. 
In ponds and slow»flowing waters, common. 1/ . June, 
Juiy. v.v. Floating in the water; flowers, as all 
the following, in spikes axillary or sometimes ter- 
minal, small and of a greenish colour. It is doubtful 
whether- this is not a new species, but I had no oppor- 
tunity to compare it in a living or dried state with the 
European plant. 
2. P. foliis inferioribus longissimis linearibus, superioribus 
lanceolatis nervosis coriaceis, omnibus petiolatis. — 
Willd. sp. pl. \ . p. J\3. 
P. foliis lanceolato-oblongis, petiolis longis. Gron.fl . 
virg. i 39. 
In ponds on the barrens of New Jersey and Carolina. 
% . July. v. v. 
3. P. foliis superioribus petiolatis ellipticis utrinque attenua- 
tis, inferioribus confertis sessilibus linearibus. Willd . 
sp.pl. l.p. 713. 
P. hybridum. Mich.Jl. amer. l.p. 101. 
In slow flowing waters of Virginia and Carolina. IjL 
June. v.v. 
4. P. foliis superioribus oppositis lanceolatis quinquenervi- 
bus brevi-petiolatis, inferioribus alternis filiformi- 
bus, spicis densis alternis folio brevioribus. — Willd, 
sp.pl: 1. p. 716 ? 
In sma.ll lakes and rivers, on the pine barrens of Jersey. 
}/ . July, Aug. v. v. The upper leaves are scarcely 
half an inch long ; the whole plant very slender. 
5. P. foliis cordato-ovatis amplexicaulibus omnibus im- 
mersis, spicis terminalibus, floribus alternis. — Mich, 
Jl. amer. 1. p. 101. Willd. sp. pl. 1. p. 713. 
Icon. FI. dan. 196. Engl. hot. 108. 
In ponds and rivers, frequent : Canada to Pensyl vania. 
11 . July, Aug. v. v. Spike of flowers only floating, 
brown. 
6 . P. foliis lanceolatis subsessilibus, costa media crassa, 
spicis longis cylindricis. Mich. Jl. amer. 1. p . 10.1, 
Willd . sp.pl. 1. p. 714. 
Icon. FI. dan. 1Q5. Engl. lot. 370- 
