23 



Sect. I. Heterophylli. Koch Syn. ed. £, p. 774. 



Folia alterna, iloralia tantum opposita , superna in planta perfecta 

 adulta natantia et, quoad figuram et saepe quoque consistentiam , a 

 submersis diversa. 



a. Folia floralia omnia coriacea et natantia. 

 1 P. natans (L. Spec 1S2) foliis omnibus longe petiolatis; ju- 

 nioribus submersis angustioribus lanceolatis oblongisve ; natantibus 

 coriaceis basi leviter cordatis ellipticis oblongisve, petiolis submersis 

 sub anthesi (ob laminam folii putredine destructam) aphyllis, pedun- 

 culis aequalibus, fructibus recentibus compressis margine obtusis, caule 

 simplici. 



P natans. Koch l. c. — Gorter Fl. ingr. p. 25. — Kalm Fl. fennic. No. 94.— 

 S. G. Gmkl. II. IV, p. 15. — Geop.gi /*. II, p. 641. 768. - Lepech. II. /, 

 p 47; ///, p. 36. 134. — Falk Beitr. II, p. 121. — Gui.deisst. It. I, p. 9. 

 49. 52. 76. 108. 167. 189; // , p. 160. 164. 255. 278. 282. 289. — GlUB. 

 Exerc. phijtol. II, p. 422. — Stephan Fl. mosq. No. 107. — Sievers in 

 Pall. n. nord. Beitr. VII, p. 267. — Geop.gi Beschreib. d. Russ. R. III, 4. 

 p 745. — Juisdz. Fl. Ulhuan. p. 47. — Makt. Fl. mosq. p. 31. — Besser 

 Enum. p. 8, No. 179. — Luce Fl. osil. p. 10. — Hofft Cat. Kurslc. p. 12. 



— Ledeb. Fl. alt. I, p. 156. — C. A. Meyer Ind. cauc. p. II. - Fkllm. 

 Ind. Kola. No. 82. — Eichw. Skizze p. 125. — Fkli.m. Ind. Lappon. No. 71. 



- Claus Ind. des. in Gobel It. II, p. 314. - Weinm. Fl. pelropol. p. 19. 



— Bongard de Veget. ins. Silcha p. 165. - Turcz. Cat. Baikal. No. 1086. 



- Hohenaok. Enum. Tntusch. p. 11. - Fleisch. et Lindkm. Fl. d Ostseeprov. 

 p> 65t _ Wikzen Casan. No. 652. — Nylander Spicil. fl. fennic. I. No. 19. 

 (excl. var. spar<;auifol.). — Nylander Parocc Pojo. No. 349. — C. A. Meykr 

 Beitr. c. Pflan*enk. d. Russ. R. V, No. 76. — C. Koch in Linnaea XXII, p. 274. 



P. rotuudifolium. Erndt. Virid. warsaw. p. 96. 



P. foliis oblongo-ovatis, petiolalis. Gmel. Fl. sib. III, p. 34, No. 24. 



Hab. in Rossia [ubique (Falk)] arctica [territor. Kola et Lapponia (Fkh.m.)], 

 septentrion ali (Oslrobothnia (Nylander in litt.), Fennia (Kalm, Nylander, 

 Schrenk in lilt.)], media [Petropoli (Gorier, Wkinm.), Nowgorod 

 (Guldenst.), Esthonia (Fleisch. et Lindem.), ins. Osilia (Luce), Livonia! 

 et Curonia (Fleisch. et Liivdkm), Litluiania! (Gilib. , Jundz , Wolfgang, 

 Eichw.) , Warsawia (Erndt.), Volbynia (Bksskr , Eichw.) , Kuisk (Hofft), 

 Mosqua (Stephan, Map.t.), Wladimir (Lepecii.) , Kasan (Wirzen) , Wiatka 

 (Lepech., C. A. Meykr) , Perm et Orenbur^ (Gkorgi)] et australi |Podolia 

 (Besser, Eichw.) . Ucrania, Jekaterinoslaw , ad Tanain et alibi in terra Co- 

 saccorum (Guldenst.), ad fl. Manitscli (J G. Gmel.), in deserti transwolgen- 

 sis rivulis Useen (Claus'], in provinciis caiwasicis (C. A. Meyer) [ad 

 fl. Terek (Guldenst.), in Iberia (C. Koch), pr. castellum l.enkoran! (Hohenack.)], 

 Sibiria uralensi (J. G. Gmel , Falk), pr. Turinsk (Lkpech.), altaira! 

 [.1. G. Gmel, Falk, Fl. alt.) in deserto sooiigoro-kirs-bisieo (Sievers), bai- 

 kalensi (J. G. Gmel., Turcz.) et orientali (J. G. Gmel.) inque Davuria 

 (Turcz.) et insula Sittba (Bongard). 4. 



/J. angustifolius : caule petiolisque elongatis , foliis natantibus ovalibus acu- 

 tiusculis. 



P. natans b. fluviatilis. Fries Novit. ed. 2, p. 28. 



P. natans /3. prolixus. Koch l. c. p. 775? 



Hab. in Rossia media [Lilliuania! (Wolfgang pl. exs.)]. 2|. 



2. P. oblongus (Viviani Fl. ital p. 2, t. 13) foliis omnibus Jonge 

 petiolatis; submersis sub anthesi persistentibus lanceolatis ; natantibus 

 coriaceis oblongis; supernis ovatis basi Ieviter cordatis, petiolis supra 

 plano-convexiusculis, pedunculis aequalibus, fructibus recentibus com- 

 pressis margine obtusis, caule simplici. 



