KUNGL. SV. VET. AKADEMIENS HANDLINGAE. BAND 55. N:0 5. 219 



On ligules etc., see under P. lucens X natans, p. 239! where the difference be- 

 tween the two is more closely determined. 



The anatomy of the stem behaves as in all the other hybrids. It generally 

 approaches to that of P. natans, but occurs with deviations, more or less obvious, 

 toward P. gramineus. It exhibits noticeable similarities to the anatomy of P. lucens 

 X natans. In many cases, however, the number of the cortical interlacunar bundles 

 is considerably reduced in P. sparganifolius. 



Distribution. Sweden. Lapland, Karesuando, 29 (and several following years) 

 L^STADius (lib. Stockholm., Uppsal., Lund., Gothenb.). This station is the original 

 habitat. LiESTADius first regarded this hybrid as a deformed P. natans, but con- 

 founded it later wdth P. gramineus. The earliest specimens are named »P. tereti- 

 caule* and »P. lineare», later on also »P. suhcoriaceus^ (specimens with floating 

 leaves). Torne 1pm, Pysakoski, 52, Fristedt (hb. Stockholm.); Little Lule River, 

 96, Vestbrlund (hb. Lund.); Majtum, 04, Wolf (hb. Limd.); Jockmock, 06, Wolf 

 (hb. Stockholm.). — Nordbothnia, Pajala, L^stadixjs (hb. Stockholm., Uppsal., Lund.); 

 Pite Pv,iver, 65, Hakansson and others (hb. Stockholm., Uppsal., Lund., Gothenb.). — 

 Angermania, Gidea River, 37, J. A — m (hb. Uppsal.). — Jemtland, Ottsjons utlopp 

 (outlet), 91, CoLLTJN (hb. Stockh., Uppsal.). — Herjedalia, Sveg in the Ljusnan, 98, 

 Enander (hb. Stockholm., Lund.). — Vermland, Sunne in Fryken, 14, Froding 

 (hb. Frod.). — Stockholm, Drottningholm, 98, Hagstrom & Lagerwall, 99, Lager- 

 w^ALL (hb. Stockholm., Lund.). — Sudermania, Gryt in Baven, 06, Sonden (hb. 

 Stockholm.). — Smoland, Malilla, Hagelsrura, 64, Bjorkgren (hb. Stockholm.), 81, 

 Hagstrom and others (hb. Stockholm., Uppsal., Lund., Gothenb.): »P. dubiusT-iS.»; 

 Misterhult, L. Laxemar, 65, Ekstrand (hb. Stockh.); Jareda, Klofdala intheEman, 

 65, Ekstrand (hb. Stockholm.). — Scania, »hb. C. M. Nyman» (hb. Stockholm.) 

 lab. »P. fluitans Roth»; Billinge, Ronnea at Stockamollan, 93, Coster (hb. Stock- 

 holm., Lund.); Tjornarp, 81, Nilsson (hb. Lund.). — More Swedish stations than 

 those are not known to me; consequently this hybrid is much rarer in Sweden than 

 X p. Zizii. 



Norway, Dovre: Goverlivandet, 65, Falck (hb. Uppsal., Lund.); Porsanger, 63, 

 hb. T. M. Fries (hb. Uppsal.); Laugen in the outlet into Mjosen, 96, Landmark 

 (hb. Stockholm., Lund.); East Finmarkia, South Varanger: Elvenses, 64, Fries (hb. 

 Uppsal.). — Lapponia rossica et fennica: Nuortijaur, 83, Hollmbn (hb. Stockholm., 

 Uppsal., Lund.); Kola peninsula, Lovanserski reka, 90, Ekstam (hb. Stockholm.); 

 Lapp, inarensis: Kaamos, 03, Torckell (hb. Stockholm., Uppsal., Lund.); Lapp, 

 kem., Par. Sodanskyla, 82, Blom (hb. Stockholm.); Lapp. Imandrse, 92, Kihlman 

 (hb. Stockholm.). — Finland: Valkjarvi, Metsakyla, Saijoki, 95, Lindeberg (hb. 

 Stockholm.); Alandia: Braktrask, 01, Palmgrbn et Klingstedt (hb. Stockholm.). — 

 Denmark, Odenseaa, Funen (Fyen), 47, Lange and others (hb. Stockholm., Uppsal.) 

 »P. fluitans rivularis Lge»; Gudena, 95, Baagoe (hb. Stockholm.); Hanbjerga, Jutl., 

 99, Baagoe (hb. Stockholm.); I have also seen it from Snesere, Ssell, Stora at Hol- 

 stebro, Jutl., and Kongea, Jutland (hb. Hagstrom). — East Baltikum, see K. R. 

 KuPFPBR, 1. c. — Germany: »Saxenwalde Nolte» (hb. Stockholm.), labelled: »P. 



