PIPER FLORA OF THE STATE OF WASHINGTON. 85 



Steins annual; spikes not mucronate. 



Fertile stems pale-brown, short-lived; sterile with many branches. 



Stems slender, 6 to 10-furrowed 5. E. arvense. 



Stems stout, 20 to 40-furrowed 6. £'. telmateia. 



Fertile stems green like the sterile, naked or branched. 



Stems obscurely ridged ; sheaths appressed 7. E.Jluviatile. 



Stems acutely ridged ; sheaths loose 8. E. palustre. 



1. Equisetum hyemale L. Sp. PI. 2: 1062. 1753. Scouring rush. 

 Type locality: "Habitat in Europae sylvis, asperis, uliginosis." 



Range: British Columbia to New England, south to California and Georgia. Europe. 

 Asia. 



Specimens examined: West Klickitat County, Suksdorf 1243, 2161, 2162; Wenache, 

 WUted, May 17, 1896; Waitsburg, Horner, February 1, 1897; Pullman, Elmer 294, July 2, 

 1896 ; Port Discovery, Wilhen Expedition. 



Zonal distribution: Transition to Canadian. 



Mr. A. A. Eaton considers that this variable species consists of several definable sub- 

 species. Ours are thus classified : 



Ridges with 2 rows of tubercles hyemale californicum Milde. 



Ridges with bands of silex. 



Sheaths loose; stems stout hyemale intermedium A. A. Eaton. 



Sheaths close; stems with fertile branches hyemale sulcsdorfii A. A. Eaton. 



The first subspecies has commonly been referred to E. robustum A. Br. 



2. Equisetum laevigatum A. Br. Am. Jour. Sci. 46: 87. 1844. 



Type locality: "On the banks of the river, below St. Louis," Missouri. 



Range: British Columbia to New York, south to California, Texas, and Georgia. 



Specimens examined: West Klickitat County, Suksdorf 2135; North Yakima, Hen- 

 derson 2263 and May 26, 1892; White S&lmon, Suksdorf 317; without locality, Vasey, 1889; 

 Old Fort Colville, Watson 472; Pullman, Piper 1733 and June 20, 1893; Kiona, Cotton 735. 



Zonal distribution: Arid Transition. 



3. Equisetum variegatum Schleich. Cajt. PI. Helvet. 27. 1807. 

 Type locality: Switzerland. 



Range: Arctic America, south to Nevada and Pennsylvania. 

 Specimens examined: West Klickitat County, Suksdorf 2099. 



4. Equisetum scirpoides Michx. Fl. 2: 281. 1803. 

 Type locality: "Ilab. in vetustis sylvis Canadae." 



Range: Alaska to Labrador, south to Washington, Illinois, and Pennsylvania. 

 Specimens examined: Box Canyon, Ereager 389; lone, Kreager 405. 



5. Equisetum arvense L. Sp. PI. 2: 1061. 1753. 



Equisetum saxicola Suksdorf, Deutsch. Bot. Monatss. 19: 93. 1901. 

 Type locality: "Habitat in Europae agris, pratis." 



Range: Alaska to Greenland, south to California and New England. Europe. Asia. 

 Specimens examined: Everett, Piper, July, 1892; Skamania County, Suksdorf 2163; 

 Falcon Valley, Suksdorf 1238; Pullman, Piper, May 15, 1893; Elmer 210, May, 1897. 

 Zonal distribution: Transition mainly. 



6. Equisetum telmateia Ehrh. Hannov. Mag. 138. 1783. 

 Type locality: European. 



Range: British Columbia to California. Europe. 



Specimens examined: Seattle, Piper, July 10, 1895; March, 1892; upper Valley Nis- 

 qually, AUen 175; Wenache, Whited 19, May 17, 1895; near Bingen, Suksdorf 1237 ; White 

 Salmon, Suksdorf 315. 



Zonal distribution: Humid Transition. 



