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



245 



f. memelanus n. f. — P. Heidenreichii AscH. et Graebner, Syn. 327, p. p.: — 

 Folia caulina 200 — 240 X 16 — 22 mm basi apiceque valde angustata. — Fig. 113. 



This form approaches to f. litMianicus which has shorter stem-leaves; from f, 

 upsaliensis it is distinguished by more elongated leaf-points, which have the 

 somewhat recurved position, peculiar to P. decipiens, and by narrower, 

 slightly rounded leaf-bases. It is to be looked upon as a cross of lucens 

 var. longifolius X perjoliatus. Cf. Kxjpffer in Riga Korr. BL, 1906, 171 ! 

 — Dr. G. Fischer has established a »f. suhperfoliatus = ser. Vollmanni 

 F. », which seems to be identical with f. typicus Tis. 



Distribution: Sweden, Scania: Krageholm Lake, 49, Z:dt (hb. 

 Uppsal.). — Holland, Frillestad, hb. E. Fries (hb. Uppsal.). — Stock- 

 holm and vicinity: Brunnsviken, 51, Z:dt and others (hb. Stockholm., 

 Uppsal., Lund., Gothenb.); Blockhusudden, 63, Fredeiksson (hb. Go- 

 thenb.); Norrstrom, 46, Lagerheim (hb. Stockholm.), f. upsaliensis; Tre- 

 horningen, 27, Bburling (hb. Stockholm.); Langsjon, 26, Bexjrling (hb. 

 Stockholm.). — Uppland: Lake Mselar ad Runsa, 88, Floderus and Tise- 

 Lius (hb. Stockholm., Uppsal.); Sigtuna: Skalgrund, 83, and Garnsviken, 

 88, Floderus and others (hb. Stockholm., Uppsal., Lund.), f. pulchellus; 

 Funbo, Danielsson (hb. Stockholm.); Safva a, 60, Tiselius (hb. Stock- 

 holm.), f. pulchellus ; Norrsunda, Holmboda Lake, in the outlet, 94, Lund- 

 berg and others (hb. Stockholm., Uppsal., Lund.); Fyris River at Ulfva, 

 28, Wahlenberg and others (hb. Stockholm., Uppsal., Lund., Gothenb.); 

 at Ensta, hb. E. Fries and others (hb. Stockholm., Uppsal., Lund., 

 Gothenb.), Leaves sometimes very large, as much as 170 X 60 mm ; at Ekeby 

 mill, 59, Tiselius (hb. Stockholm., Uppsal.); at Jasevad, 84, Tiselius near 

 (hb. Stockholm., Uppsal., Lund.). — (S^tdlermanw in Uttran and Malmsjon, 

 Sodertalje; and West-Goihia in Husgarde lake and OkuU lake (hb. Hagstr.). 



Denmark, Susa, Ssell., 95, Ostenfeld— Hansen and others (hb. 

 Stockholm., Lund.); Hald so Jutl., 70, Nielsen (hb. Uppsal.); Gudena 

 ad Kongensbro, Jutland, 97, Baagoe (hb. Stockholm.). — England, Cam- 

 bridgeshire, 84, Fryer (hb. Stockholm., Uppsal., Lund.). This plant, be- 

 side a specimen of P. prmlongus Wulfen, labelled sHerb. Florae germa- 

 nicse exsicc. curante LuDWiG Reichenbagh N:o 2501 Potamogeton longi- 

 folius Gay. Golssen in der Nieder Lausitz. Apoth. Burkhardt», are 

 determined by P. Graebner as » Potamogeton prcelongus x lucens {P. de- 

 cipiens NoLTE in Koch Syn. ed. 2. 779 (1844)) var. Bahingtonii (Benn. 

 Journ. of Bot. XXXIT, 204, (1894)) A. u. G., Syn. I, 332» (hb. Berolin., 

 P. Graebner's own hand). — Germany, Vratislavise, Uechtritz (hb. 

 Stockholm., Uppsal.). Kilife, Noltb (hb. Stockholm., Uppsal.), »P. dici- 

 piens NoLTE»: Stem-leaves 75 — 120 X 20 — 30 mm, ligules short, very soon decaying; 

 Holstein und Lauenburg, E. F. Nolte (hb. Uppsal.), ex hb. E. Fries, labelled: 

 »Herb. der Schl.— Hoist.— Lauenb. Fl. no. 715 (1838) publicirt Nolte» (Nolte's own 

 hand) : Leaves 100 X 25 mm. These specimens are the so-called P. lucens X prce- 



Fig. 113. P. 

 decipiens Nolte 



f. memelanus 

 Hagstr. Stem- 

 loaf at the pri- 

 mary spike, -[, 

 ca. 13-nerved. 



