PIPER FLORA OF THE STATE OF WASHINGTON. 107 



ARISTIDA. 



1. Aristida purpurea robusta (Merrill). 



Atidida longiscta robusta Merrill, U. S. Dept. Agr. Div. Agrost. Circ. 34: 5. 1901. 



Type locality: "Indian Creek, Montana." 



Range: South Dakota to British Columbia, south to Nebraska and Wyoming. 



Specimens examined: A]m&, Elmer 536; Rock ls\iin(i, Sandherg (& Leiberg 439:Spoka.ne, 

 Piper 2597: Wavvawai, Brodie, July, 1898; Kelly's Bar, Snake River, Brodie, July, 1898; 

 Cow Creek, Grijfiihs d' Cotton 288; Lyons Ferry, Griffiths & Cotton 547. 



Zonal distribution; Upper Sonoran and Arid Transition. 



Nuttall's type of ^4. purpurea in the Philadelphia Academy of Sciences was, in my 

 opinion, misunderstood i)y Mr. Merrill. The type certainly belongs to the group of forms 

 Merrill includes under ^4. Jongiseta Steud., and has nothing to do with the species with 

 which Merrill associates the name purpurea. 



STIPA. 



Awns 10 to 20 times longer than the lemmas. 



Plants glabrous 8. S. comata. 



Plants pubescent So. S. comata intonsa. 



Awns 4 to 7 times longer than the lemma. 

 Awns plumose. 



Ligule 1 mm. long or less. 



Sheaths glabrous 1 . >S'. occidentalis. 



Sheaths pubescent 2. .S'. elmeri. 



Ligule 2 to 4 mm. long 'A. S. thurberiatia. 



Awns only slightly pube.scent or scabrous. 



Callus very short, obtu.se: spikelets stout 4. S. leminoni. 



Callus acute or acuminate. 



Sheaths pubescent 5. .S". ^viUiamsii. 



Sheaths smooth or only .scabrous. 



Awn.s 1 to 3 cm. long tl. <S'. minor. 



Awns 3.5 to 6 cm. long 7. .S'. nelsoni. 



1. Stipa occidentalis Thurb. Bot. King Explor. 380. 1871. 

 Stipa drida Vasey, Bull. Torr. Club 10: 42. 1883. 



Stipa stricta sparsiflora Vasey, Contr. Nat. Herb. 3: 51. 1892. 



Stipa oregonensis Scribner, U. S. Dept. Agr. Div. Agrost. Bull. 17: 1.30. 1899. 



Type locality: "Yosemite Trail, California." 



Range: Wa.shington to Nevada and California. 



Specimens examined; EUensburg, Piper 2583; Twenty-five Mile Creek, Okanogan 

 County, Gorman 617; Clealum, Hender.wn 2254; Mount Adams, Henderson 2256; Ophir, 

 Elmer 515; without locality, Sulsdorf in 1882; Mount Baldy, Cotton 1755; Wenache 

 Mountains, Cotton 1675; Stehekin, Griffiths d' Cotton 21. 



Zonal distribution: Arid Transition. 



2. Stipa elmeri Piper & Brodie, U. S. Dept. Agr. Div. Agrost. Bull. 11:46. 1898. 

 StijM vindula puhescens Vasey, Contr. Nat. Herb. 3:.%. 1892, not Stipa pubeseens R. Br. 



1810. 



Type locality: Empire City, Nevada, according to the label on the type specimens. 



Range: Washington to Nevada. 



Specimens examined: West Klickitat County, Suhsdorf. June 17, 1883; Nile, Henderson 

 2253; Cascade Mountains, Vasey in 1889; Chelan, Elmer 487; Ophir, Elmer, August, 1897; 

 Spokane, Piper 2276, 2601 ; Steamboat Rock, Griffiths t£' Cotton 441. 



Zonal distribution: Arid Transition. 



