KtJNGL. SV. VET. AKADEMIENS HANDHNGAE. BAND 55. N:0 5. 189 



Distribution. Eurofe. Germany, many stations, the most northern at Konigs- 

 berg, 91, Schultz (hb. Uppsal.). — Switzerland, Geneva, 70, Ayassb (hb. Uppsal.). — 

 France, Nantes, Loir, 81, Lloyd (hb. Stockholm.), Aix-les-Bains, Boulltj (hb. Stock- 

 holm,). — Italy, Sicilia: Palermo, Siracusa etc. (hb. Stockholm., Uppsal.). — Spain, 

 Andalusia, Ronda, 89, Reverchon (hb. Uppsal. et Lund.), Guadalhorce, 83, Nilsson 

 (hb. Uppsal.). — Austria, several places (hb. Stockholm., Uppsal., Lund.). — Herzegovina, 

 1889, MuEBECK (hb. Stockholm., Uppsal., Lund.). — Russia, Lithuania, Wilna, Wolf- 

 gang (hb. Stockholm., sP. petiolatus»); Volhynia and Podolia (hb. Petersb.). — 

 Greece, In valle Cephissi, 88, Dr. Heldreich, and by him labelled: P. natans L. f. 

 grceca (hb. Stockholm.). — Asia, Persia prope Schiras, 42, Kotschy (hb. Stockholm., 

 Uppsal.). — Ind. or. Penjab, Thomson (hb. Stockholm.), fruit not deviating; Utaca- 

 mund, Hohenackbr (hb. Uppsal., ^P. indicus»); Chiwa. — N. America, Cuba, Wright, 

 1860—64 (hb. Stockholm.), PI. cubenses Wrigthianas n:o 603, 604, 3202; one sheet 

 of n:o 603 contains a dubious form, possibly a hybrid. Porto Rico, prope Bayamon, 

 85, Urban, prope Utuado, 87, Sintenis (hb. Stockholm.), the former of these 

 specimens, determined by Urban, the latter by Bennett, but both dubious, both 

 lacking, as far as I can find, serrulation in the submersed leaves; probably they 

 belong to what I call P. insulamis, the floating leaves of which, however, are nar- 

 rower. To P. Nuttallii, as it seems to me, they can not possibly be referred (cf. 

 Graebner, Potam. 1907, 56!). Antigua, 41, Liebmann (hb. Plaun.). — Mexico, Casa 

 de Tena (hb. Stockholm). Jicaltepec and Vera Cruz, 41, Liebmann (hb. Haun.). — 

 As to the TJ. S. of Am. I have seen it from Courtland, Minn., 92, Ballard (hb. Stock- 

 holm.), Cayuga-Lake, N. Y., 84, Morong (hb. Stockholm.), North Ferrisbergh, Vt, 85, 

 MoRONG (hb. Stochholm.), New Engl., Morong (hb. Uppsal.), together with a top of 

 P. gramineus X nodosus; Niagara, E. Tuckerman (hb. Uppsal.), large-leaved 100 X 40 

 mm; near Washington, Seaman (hb. Uppsal.), small and narrow leaves; Lees Lake, Colo- 

 rado, 97, Crandall (hb. Uppsal.); Texas. — Canada: Que., Ont., B. C. (hb. Haun.). 

 — S. America: Rio de Janeiro (hb. Christ.). — Africa, Algeria, 72, Warion (hb. Stock- 

 holm.); Socotra, 80, Balfour (hb. Stockholm.), Madeira in rivulo prope Machico, 65, 

 Mandon (hb. Stockholm.), PI. Maderenses, n:o 232, labelled: »P. gramineus L. var., P. 

 heterophyllus v. f. Lloyd, F1. Quest, P. Machicatncs Mandon in schedula (Coss.)»; Ma- 

 chico, 28, HoLL (hb. Lund.). Gran Canaria, 97. Gelert. — Rhodesia, in Zambese River, 

 a little above the Victoria falls, 1911, R. E. Fries (hb. Uppsal.), f. angustissimus 

 Hagstr. — Prope Tripoli: Dr. Rothman (hb. Stockholm.): of low growth, very 

 short internodes, ligules short, 15 — 20 ram, with rather low ridges, at last ripped 

 up into threads ; fruit of the same shape as in P. nodosus but less, 2,6 X 2 mm and 

 with indistinct dorsal keel. Stem-anatomy not deviating. — Egypt. — Mascarene 

 Is. »Boivin pi. ins. Borboniae* (hb. Christ.). — »0-Wohy» ded. Chamisso, and 

 Marianne Is. (hb. Haun.). 



In Europe, thus, the species spreads northward to the 55 parallel (Kcinigsberg, 

 see above), but does not occur in Holland (according to Vuyck I.e.), Great Britain, 

 and Ireland. Nor have I seen it from Portugal. From this non-occidental occur- 

 rence we may be permitted to conclude that P. nodosus is an easterly plant with its 



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