PIPER FLORA OF THE STATE OF WASHINGTON. 97 



Floating leaves none. 



Leaves all oblong or lanceolate. 



Base of leaves clasping; apex acuminate 1 . P. ferfoUatnx. 



Base of leaves not clasping; apex not acuminate. 



Leaves obtuse, cucullate, sessile 8. P. ]>raelon(i>i.s-. 



Leaves acute, short-petioled 9. P. lucens. 



Leaves all narrowly linear. 



Stipules adnate to the sheathing base of the leaf. 



Leaves setaceous, 1 to .5-nerved 13. P. peciinatus. 



Leaves ]inear-lancet)late, many-nerved 14. P. rohbinsii. 



Stipules free. 



Leaves tape-like; spike cylindric; fruit large 10. P. zosferaefoJiiis. 



Leaves not tape-like; spike not cylindric; fruit small. 



Spike capitate; peduncles very short \l. ]'. californiciis. 



Spike interrupted; peduncles long 12. P. pusiJlus. 



1. Potamogeton natans L. Sp. PI. 1: 126. 17.53. 

 Type loc.vlity; European. 



Range: North America. Europe. Asia. 



Specimen.s examined: Cascade Mountains, 49°, Li/aU in 1859; Oyhut, Lamh 12.59; 

 Tacoma, Flett 13.5; Falcon Valley, Suhsdorf, July 17, 1886: Pend Oreille River, L>jaU in 

 1X61. 



2. Potamogeton nuttallii Cham. & Schleclit. Linnaea 2:226. f. l].f.2o. 1827. 

 Potamogeton daytonii Tuck. Am. .Tourn. Sci. 14: 38. 1843. 



Type locality: None given. 



Range: Washington and Oregon to Nova Scotia and South Carolina. 



Specimens examined: ISlontesano, Heller 4072; lUv&co, Henderson mlSSG: Lake Wash- 

 ington, Piper, September, 1892; Mount Constitution, Henderson 2477; Spokane County, 

 Henderson 2476; Waitsburg, Horner R16. 



3. Potamogeton amplifolius Tuck. Am. Jovun. Sci. II. 6: 22.5. 1848. 

 Type locality: Cambridge, Massachusetts. 



Range: British Columbia to Ontario, south to Washington and Nebraska. 

 Specimens examined: Coupeville, Gardner 421; Pullman, Henderson 2474; Kalispel 

 Lake, Kreager 441; Whatcom County, Sulsdorf, .\ugust 1. 1890. 



4. Potamogeton alpinus Balbis, Mem. Acad. Turin 7:323. 1803. 

 Potamogeton riifescens Schrad.; Cham. Ad. Fl. Ber. .5. 1815. 



Type locality: European. 



Range: British Columbia to Labrador, south to California and New Jersey. 

 Specimens examined: Mount Adams, Snl'sdorf, September, 1879; Trout Creek, Suls- 

 dorf 2172. 



5. Potamogeton heterophyllus Schreb. Spicileg. Fl. Lips. 21. 1771. 

 Ti'PE locality: "In stagno ad Lindenthal," Germany. 



Range: Throughout most of North America. Europe. 



Specimens examined: Lake Chelan, Lake d.' Hull 614; Okanogan River, Watson 396; 

 Tumwater Canyon, Sandherg & Leiberg 524; Falcon Valley, Snksdorf, August, 1885. 



6. Potamogeton lonchites Tuck. Am. Journ. Sci. II. 6:226. 1848. 



Type locality: "Common in New England and extending southward to V'irginia." 

 Range: Washington to New Brunswick, south to California and Florida. 

 Specimens e.xamined: Clallam County, Elmer 2798; Silver Lake, Henderson 2475; 

 Okanogan River, Watson 398, Pend Oreille River, Lgall in 1861; Whitman County, Hen- 

 derson 2473; Union Flat, Piper, August 4, 1899, without locality, Vaseg in 1889. 

 29418—06 M 7 



