KUKGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. N:0 5- 47 



Fl. 1889, 56) records it from Skellefteå, too. At all events, we have its proper 

 distribution area to the south of this latitude. As regards its occurrence in Swedish 

 fresh water the Museums suggest that it appears in Scania, Trelleborgs å, hb. Ag 

 (hb. Lund.), Höjeå at Lund, 49, Z. (hb. Lund.), Börringesjö, hb. Duben (hb. Lund.), 

 Råbelöfsjön, 86, Nilsson (hb. Lund.); Smoland Skärstad, 86, Rendal (hb. Lund.), 

 Munksjön, 09, Ekman (hb. Frödtng); Westgothia, Ösan, 81, Hulth (hb. Uppsal.), Aspö- 

 sjön, 64, Nordstedt (hb. Uppsal.), N. Ving, 05 (hb. Alm), Ulricehamn, 46 (hb. Wester- 

 lund); Ostrogothia, Tåkern, 43 (hb. Uppsal.), Vadstena in a rivulet near Starby (hb. 

 Stockholm.); Suderma?inia, Sparreholm, Nyman (hb. Stockholm.), Vårdinge, Sjögård, 94, 

 Trägårdh (hb. Uppsal.); Uppland, Mälaren, several stations: Kongshamn 1797 (hb. 

 Uppsal.), Sigtuna, 89, Floderus (hb. Stockholm.) etc, Fysingen, 95, Tiselius (hb. 

 Stockholm, and Uppsal.), Valloxen, 84, Tiselius (Stockholm, and Uppsal.), Uppsala 

 Björkby, 66, ährling (hb. Uppsal.), Fyris 1859, Zetterstedt (hb. Uppsal.), Ulfva, 

 66, Tiselius (hb. Stockholm.) etc. S. Almquist (1. c.) also records it from Silfberg 

 in Dalecarlia ca. 60° 20' Lat., thus not so far towards the north as in the Gulf of 

 Bothnia. On the other hand P. filiformis proceeds to Jemtland and Lapland! A 

 good deal of materials, especially from the Baltic, is deposited in the Museums re- 

 f er red to. 



A great many forms belonging to this variety are distinguishable: 



f. laxus Tisel., Potam. suec. exsicc, fasc. III, 1897, n. 120 — 122: — Caulis 

 filiformis tenuior, superne internodiis brevissimis; pedunculus ssepe brevior. 



Distribution: Sweden, rather common, recorded from Gefle (hb. Lund.) and 

 south ward along the Uppland coast and from the Lake Mselar, Sudermannia, Ostro- 

 gothia and Smoland. — Russia, Sarepta, 85, Becker (hb. Uppsal.). — England, 

 Hedge Court Mill Pond, Surrey, 83, Beeby (hb. Stockholm.), Chatteris, Cambs., 84, 

 Fryer (hb. Uppsal.). — Germany at several places in Brandenburg, Sachsen etc. — 

 Tirolia austr. (hb. Lund.). — Italy, Trento, Sardagna (hb. Uppsal.). 



f. submarinus Fries, Novitiae Fl. suec. 1828, 53: — »Caule capillari inferne nudo, 

 fol. subdistantibus, ultimis subternis approximatis capillaceis, pedunculo brevissimo 

 unico seminum verticillo capitato. » 



According to the description this form coincides with f. laxus except as to 

 the spike, which is capitate. It is said to occur »in aquis salsis vadosis», but I 

 must confess that I ne ver saw this form. In »hb. E. Fries», at Uppsala, I have 

 found a plant from Westbothnia, Nordmalingsfjärden, 1864 coll. by LiESTADius and 

 labelled »Potamogeton pectinatus L. — submarinus Fr.», however not by Fries him- 

 self, but this was found to be the common form of P. filiformis with spike and 

 peduncle evoluted in the usual mode. Thus it cannot be the original plant of Fries. 

 Most likely f. submarinus Fr. is a f. laxus with deformed spikes. In Summa Veg. 

 1846, Fries does not mention it more. 



f. glaueescens Cham. et Schl., in Linnaea, 1827, 165: — »capillaceus, 1—1 Va ped., 

 ramosissimus. Vaginse margine valde albo-scariosse nec amplse, 7 circ. lin. longse. 

 Folia tenuissima, densissima, capillacea 1 '/a— 2 poll. longa. » 



This form comes near to f. laxus Tis., but is more richly branched and with 



