22 FLOBA OF PHILADELPHIA. 



With submerged leaves only. 



Without propagating buds and without glands. 



Leaves with broad blades, mostly lanceolate or ovate, many- 

 nerved. 8. P. perfoliatus. 

 Leaves with narrow blades, linear or oblong-linear, several- 

 nerved. 12. P. foliosus. 

 Leaves with narrow blades, capillary or setaceous, 1-nerved or 

 nerveless. 9. P. confervoides. 

 With propagating buds or glands, or both. 

 With buds, but without glands. 



Leaves serrulate, 3-7-nerved. 10. P. crisjms. 



Leaves entire, with 3 principal and many fine nerves. 



11. P. zosteraefolius. 

 With both buds and glands. 



Glands large and translucent, buds rare. 



13. P. obtusifolius. 

 Glands small, often dull; buds common. 



14. P. pusillus. 

 Stipules adnate to the leaves or petioles. 



With both floating and submerged leaves. 



Submerged peduncles as long as the spikes, clavate, often recur^-ed. 



15. P. diversifolius. 

 Submerged spikes sessile or nearly so. 16. P. Spirillus. 



With submerged leaves only. 



Drupelets without keels or obscurely keeled. 17. P. pectinatiis. 

 Drupelets strongly 3-keeled. 18. P. Eobbinsii. 



1. POTAMOGETON NATANS L. M. p. 42. Ponds and streams. Summer. 



2. POTAMOGETON Oakesianus Eobbins. M. p. 42. Still water. Summer. 



Burlington— Brown Mills (C). Atlmitic—Bstelville (C), Mill Pond 

 10 miles west of Atlantic City (He.). Oceon— Forked Eiver (Le.). 



3. POTAMOGETON AMPLiFOLius Tuckenn. M. p. 43. Ponds and rivers. 



Summer. 



Philadelphia — Schuylkill above Philadelphia (Cr.). Buds — Hoot's 

 Dam (Fr.). Delaware— Rifle Range (Cr.). Le7itc//i— Lehigh River (Kr.). 

 Northampton— (P.) . 



Camden— In the Delaware (C). Gloucester— Big Timber Creek (He.). 



4. POTAMOGETON PULCHER Tuckerm. M. p. 43. Ponds. Summer. 



JSmcA's— Bristol (Cr.). Lehigh— {P.). Northampton— {P.). 



Gioitcesier— Eepaupo (Li.) (Wn.). ^aZem— Elmer (C). Cape May— 

 Wildwood (C). Atlantic— k.t\?int\Q.C\tj (C). Oceo?i — Toms River (C). 



New Castle— Col. Andrews, T at nail ; Newport, Commons; Shelpot 

 Creek, Cedar Swamp, Commons. 



5. POTAMOGETON NuTTALLii Cham. & Sch. M. p. 43. Ponds and streams. 



Summer. 



6. POTAMOGETON LONCHITES Tuckerm. M. p. 43. Ponds and slow streams. 



Late summer. 



Philadelphia— Angora, C. A. Boice (Te.). Delaware— Tirn.cViVa. (B. 

 Sm.). Lojicosier— Opposite Marietta (Le.), Safe Harbor (P.). North- 

 ampfo?!— Easton (P.). 



Gloucester— Mickleton (He.), Swedesboro (Li.). 



New Castle— C'herr J Island, Commons. 



7. POTAMOGETON HETEROPHYLLUS Schreb. M. p. 44. Still or flowing water. 



Summer. 



