334 BOTANICAL GAZETTE [april 



Wheeleri of S. longifolia (see following). Rydberg described this 

 form as S. luteosericea (in Britton, Man. 316. 1901) and kept the 

 name in his Fl. Color. 94. 1906, while he makes it a synonym of his 

 S. exigua in 191 7 (Fl. Rocky Mts. 192), as Ball has already done 

 in 1909. The type came from western Nebraska, Banner County. 

 I think it best at present to keep this form separate under the name 

 S. EXIGUA var. luteosericea, nov. var., and I provisionally refer 

 the following specimens to it in the hope that collectors may pay 

 attention to the localities mentioned and try to get a better under- 

 standing of this variety by studying it carefully in the field a; io its 

 association with typical exigua and with S. longifolia. I can hardly 

 point out a good character by which to recognize this form, but its 

 pubescence is a little more villose, and the aments are more loosely 

 flowered than in typical exigua or var. stenophylla. 



Specimens examined. — Western Nebraska: Banner County, Lawrence 

 Fork, July 8, 1891, P. A. Rydberg (no. 368 partim, f. type; N.); Kearney 

 County, dry creek, June 13, 1891, P. A. Rydberg (no. 369, m. syntype; N.); 

 Scotts Bluff County, Platte bottom, in Mitchell Valley, August 4, 1891, P. A. 

 Rydberg (no. 368 partim, fr.; N.). — ^Colorado: Weld County, Greeley, July 23, 

 1896, L. H. Pammel (no. 200, fr., 201, m.; M.) ; Larimer County, without exact 

 locality, plains, alt. 1500 m., June 26, 1895, C. F. Baker {Patterson no. 9842, m., 

 f., rather typical, the male specimen almost identical with exigua typica); 

 Fort Collins, near river, June 26, 1896, L. H. Pammel (no. 202, f.; M.); same 

 locality, meadow near river, August 6, 1898 (Hb. Agr. CoU. Colo., no. 2343, fr.; 

 C); Morgan County, Fort Morgan, June 1896, L. H. Pammel (no. 204, St.; 

 M.) ; Fremont County, Canyon City, banks of the Arkansas River, September 

 24, 1874, G. Engelmann (st., M.; vel var. stenophylla); Boulder County, August 

 I [and 21 ?], 1884, July 20, 1885, G. W. Letterman (fr. ; M.); Denver County, 

 Denver, August 20, 1884, G. W. Letterman (fr.; M.). — S. Dakota: Butte 

 County, Indian Creek, along flood plain, July 31, 1911, 5. S. Visher (no. 2640, 

 St.; C; f. incerta); Bennett County, Little White River, vaUeys, August 15, 

 1911, 5. 5. Visher (no. 2274, st.; C; rather uncertain, similar to S. longifolia 

 Wheeleri) . 



There remains another form the proper interpretation of which 

 raises many difficulties. It was described by Henderson as 5*. 

 longifolia tenerrima from specimens collected by the author in 

 Idaho, Elmore, and Canyon counties. At first sight it can hardly 

 be distinguished from what I call S. longifolia var. pedicellala (see 

 later), especially from such specimens as Easlwood's no. 465, but a 



