Nelson — The Genus Psilostrophe. 23 



admits of no question. The following series of specimens, some distrib- 

 uted as one and some as the other, are remarkably homogeneous, as 

 might be expected, since most of them are from type locality, which is 

 the same for both. A fine example of this by Mr. Osterhout shows that 

 the species under favorable conditions is not. unusually low. 



Specimens examined. Grand Junction, Colorado, M. E. Jones, 5474 

 (type), June, 1894; id. May, 1895; C. F. Baker, No. 106; S. G. Stokes, 

 1900; D. A. Saunders. No. 405, 1893; C. F. Baker, No. 14, Montrose; 

 J. H. Cowen, No. 27G, Hotchkiss; G. E. Osterhout, Rifle, Colorado. 



6. Psilostrophe sparslflora (Gray) n. comb. 



RidddUa tagetina sparsiflora Gray, Syn. PI. 1:318. 188G. 



Stems 1-3 dm. high, singly from the several crowns of the woody root, 

 noticeably striate, green but with" a sparse hirsute pubescence which 

 extends to the leaves: leaves alternate, linear, often narrowly so, rarely 

 with one or two lateral teeth, 3-5 cm. long; the lower usually subspatu- 

 late and decurrent upon the long slender petiole; heads corymbose on 

 the slender pedunculate uppermost branchlets; ray flowers 3, the ligule 

 7-8 mm. long and noticeably broader, sprinkled with minute resin or 

 wax particles, the tube very short and only partially closed, the style 

 protruding from the fissure; disk flowers 10 or fewer, tubular, fully 

 twice as long as the unequal, acute or more or less lacerate-tipped pap- 

 pus pale;c; akenes angled, not perceptibly striate. 



This seems to be a singularly good species. I take as probably typical, 

 of the plant that Dr. Gray so named as a variety, the form that occurs 

 in Utah. That is truly with few heads. The Arizonan form is more 

 freely flowered and with more numerous and more fascicled stems, but 

 in all essentials they are the same. The green almost glabrous aspect, 

 the regular alternation of the slender axillary branches and the almost 

 umbellately-clustered slender-peduncled heads are characters quite 

 peculiar to this species. 



Specimens examined.— Utah: M. E. Jones, No. 5296, Pahria Canyon, 

 1894; Dr. Palmer, No. 246£, Southern Utah, 1877. Arizona: J. B. Lei- 

 berg, No. 5624, 1891; L. F. Ward, 1891; D. T. MacDougal, No. 229, 1898; 

 H. H. Rusby, 1883: F. H. Knowlton, Nos. 182 and 272, 1889; M. E. Jones, 

 Nos. 4038 and 6050a, 1884 and 1894: J. W. Tourney, No. 63S, 1892. 



I place here somewhat doubtfully Mr. Jones's No. 5291i, Pahria, Utah, 

 1894. 



