8 NORTH AMERICAN FLORA [Volume 34 



5. Psilostrophe divaricata Rydberg, sp. nov. 



A low perennial with woody caudex; stems about 2 dm. high, green, sparingly pilose and 

 glandular-granuliferous, angled and striate, much branched; branches ascending-spreading; 

 basal leaves linear-oblanceolate, 3-5 cm. long, loosely villous, with tufts of hairs at their bases; 

 stem-leaves linear, entire or some of them with a few short lobes; heads rather numerous, 

 corymbose; involucre 4 mm. high and 2 mm. broad; ligules mostly 3, about 4 mm. long, 

 shallowly 3-cleft; disk-corollas 4-7; achenes glabrous, angled; squamellae lanceolate, acute, 

 about half as long as the disk-corollas. 



Type collected in the Grand Canyon of the Colorado, Arizona, 1897, D. T. Allen (herb. N. Y. 

 Bot. Gard.). 



Distribution: Arizona and Chihuahua. 



6. Psilostrophe Hartmanii Rydberg, sp. nov. 



A low shrub, 3-6 dm. high; stem rather densely woolly below, less so above; branches 

 ascending, 2-4 cm. long, villous; leaves linear or linear-oblanceolate, 2-4 cm. long, 2-4 mm. 

 wide; heads numerous; peduncles less than 1 cm. long; involucre 5 mm. high, 3-4 mm. 

 broad; ligules 3, orange, 2-3 mm. long, shallowly 3-lobed; disk-flowers 6-8; achenes gla- 

 brous, striate; squamellae lance-elliptic, obtuse. 



Type collected near Laguna de Guzman, Chihuahua, July 16, 1891, C. V. Hartman 726 (herb. 

 N. Y. Bot. Gard.). 



7. Psilostrophe grandiflora Rydberg, sp. nov. 



A green perennial, woody at the base; stems sparingly villous with ascending branches; 

 leaves entire, spatulate or the upper linear-oblanceolate, the lower 3-6 cm. long, green, sparingly 

 villous; heads corymbose, rather numerous; peduncles slender, 2-4 cm. long; involucre about 

 6 mm. long, 3-4 mm. broad; ligules mostly 3, bright-yellow, 8-10 mm. long, rather shallowly 

 3- or 4-toothed; disk-corollas 7-10, glabrous; achenes 5-angled, glabrous, striate; squamellae 

 ovate- or lance-oblong, obtuse, less than half as long as the disk-corollas. 



Type collected near Cedar Gulch, Paradise, Arizona, Blumer 1709 (herb. N. Y. Bot. Gard.). 

 Distribution: Arizona, New Mexico, and Sonora (?). 



8. Psilostrophe lanata (A. Nelson) Hay, Miller & White, Proc. 

 Biol. Soc. Wash. 16: 186. 1903. 



Psilostrophe tagetina lanala A. Nelson, Proc. Biol. Soc. Wash. 16: 21. 1903. 



A perennial, woody only at the base, which is densely woolly; stems 3-4 dm. high, long- 

 villous, angled and striate, usually with strongly ascending branches; basal leaves spatulate, 

 petioled, 5-10 cm. long, rather densely long- woolly, at least when young; lower stem-leaves 

 often toothed or lobed, with oblong divisions; upper stem-leaves linear or linear-oblanceolate; 

 heads rather numerous; peduncles mostly short, 1-2 cm. long; involucre about 6 mm. long, 3 

 mm. broad; ligules 3-5, orange or bright-yellow, 6-8 mm. long, shallowly 3-lobed; disk-corollas 

 7-10; achenes glabrous, striate; squamellae lance-elliptic, about half as long as the disk-corollas. 



Type locality: Texas. 



Distribution: Western Texas to New Mexico and Chihuahua. 



9. Psilostrophe Bakeri Greene, PI. Baker. 3: 29. 1901. 



Riddellia tagetina pumila M. E. Jones, Proc. Calif. Acad. II. 5: 700. 1895. 

 Psilostrophe pumila A. Nelson, Proc. Biol. Soc. Wash. 16: 22. 1903. 



A perennial with taproot and branched woody caudex; stems long-villous, 1-2 dm. high, 

 branched above; lower leaves broadly spatulate, 5-10 cm. long, densely long-villous, entire, 

 the upper linear-oblanceolate or oblong; heads corymbose; involucre 6-8 mm. long, 4-5 mm. 

 broad; ligules 4-6, shallowly 3-lobed, 8-12 mm. long; disk-flowers 8-10; achenes glabrous, 

 striate; squamellae ovate, obtuse, denticulate, less than half as long as the disk-corollas. 



Type locality: Montrose, Colorado. 

 Distribution: Western Colorado. 



