120 
natans ? 
Sluitans. 
heterophyl- 
lum. 
setaceum. 
perfoliatum. 
TETRANDRIA TETRAGYNIA, 
154. POTAMOGETON. Gen. pl. 234. 
1. P. foliis longe petiolatis natantibus sublanceolato-ovali- 
bus, primariis nonnullis subcordatis. Mich. ff. amer. 1, 
p. 101. 
In ponds and slow-flowing waters, common. 7. June, 
July. 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. 1. p. 713. 
P. foliis lanceolato-oblongis, petiolis longis. Gron. fl. 
virg. 139. i MTS 
In ponds on the barrens of New Jersey and Carolina. 
Y. July. v. v. 
3. P. foliis superioribus petiolatis ellipticis utrinque attenua- 
tis, inferioribus confertis sessilibus linearibus. Willd. 
: sp. pl. I p. 713. ; ; [eod $5 
P. hybridum. Mich. fl. amer. 1. p. 101. 
June. v.v. 
In slow flowing waters of Virginia and Carolina. y. 
* 
4. P. foliis superioribus oppositis lanceolatis ee oil 
bus bieri- petiofitis E inferioribus kernik liformi- 
bus, spicis densis alternis folio brevioribus, — JP i 
sp. pl. 1. p.716? ; 
In small lakes and rivers, on the pine barrens of Jersey. 
Y. July, Aug. v.v. The upper leaves are scarcely - 
half an inch long ; the whole plant very slender. 
5.P. folis cordato-ovatis amplexicaulibus omnibus im- 
mersis, spicis terminalibus, floribus alternis.—JM 
Jl. amer, 1. p.101. Willd. sp. pl. 1. p. 713. 
Icon. Fl. dan. 196. Engl. bot. 168. — 
In ponds and rivers, frequent: Canada to Pensylvania. 
Y. July, Aug. v.v. Spike of flowers only floating, 
brown. |. —. MUR 
6. P. foliis lanceolatis subsessilibus, costa media crassa 
spicis longis cylindricis. Mich. fl. amer. 1. p. 101 
Willd, sp. pl. 1. p.714. - ; 
Icon. Fi. dan. 195. Engl. bot. 376. 
