CARDUACEAE. 
343 
21. Chrysothamnus serralatus (Torr.) Rydb. ( Bigelovia Douglasii ser- 
rulata A. Gray; C. glaucus A. Nels.) On dry plains of Wyo. and Utah to 
Colo.—Alt. 5000-8000 ft.—Gypsum; road to Steamboat Springs; Cottonwood 
Lake; South Park, near Jefferson; North Park; headwaters of Clear Creek; 
Twin Lakes; Middle Park. 
22. Chrysothamnus latifolius (D. C. Eaton) Rydb. ( Bigelovia Douglasii 
latifolia A. Gray) On dry plains from Mont, and Wash, to Colo. 
23. Chrysothamnus lanceolatus Nutt. ( Bigelovia Douglasii lanceolata A. 
Gray) On dry plains and hills from Mont, and Wash, to Colo.—Alt. 7000- 
8500 ft.—Cottonwood Lake; Grizzly Creek; Black Canon; Cerro Summit; 
North Park, near Walden; Hayden, Routt Co. 
24. Chrysothamnus puberulus (D. C. Eaton) Greene. ( Linosyris viscidi- 
dora puberula D. C. Eaton) On dry plains and hills from Mont, and Wash, 
to Colo, and Utah.—Alt. 8000-9500 ft.—Pitkin; Parlin; South Park, south¬ 
east of Jefferson. 
25. Chrysothamnus Vaseyi (A. Gray) Greene. ( Bigelovia Vaseyi A. Gray) 
In the mountains of Wyo., Colo, and Utah.—Alt. about 7500 ft.—Middle 
Park; Greene, North Park; Gunnison; Squaw Hill, above Cimarron. 
10. ISOCOMA Nutt. 
Bracts acute, linear-lanceolate. 1. I. pluridora. 
Bracts obtuse or obtusish, linear, oblong or oblanceolate. 2. I. Wrightii. 
1. Isocoma pluriflora (T. & G.) Greene. ( Bigelovia pluridora A. Gray) 
On plains of Colo.—“ On the Arkansas.” 
2. Isocoma Wrightii (A. Gray) Rydb. ( Bigelovia Wrightii A. Gray) On 
banks and in saline soil from Colo, to Tex. and Ariz.—Alt. 4000-5000 ft.— 
San Juan Valley ( Brandegee ). 
11. SIDERANTHUS Nutt. 
Leaves spinescently toothed, not pinnatifid. 
Heads discoid; perennial with woody caudex. 1. S. 
Heads radiate; annual. 2. 5 . 
Leaves pinnatifid at least the lower ones. 
Stem more or less floccose or cinereous, especially when young. 
Plant cinereous-pubescent, more or less glandular. 3. . 9 . 
Plant more or less floccose, not at all glandular. 4. 6”. 
Plant neither floccose nor cinereous. 
Plant glabrous or slightly glandular-puberulent. 5. S. 
Plant decidedly pubescent. 
Plant finely puberulent. 6. S. 
Plant hispid-strigose. 7. 5 '. 
grindelioides. 
annuus. 
australis. 
spinulosus. 
glaberrirnas. 
puberulus. 
gracilis. 
1. Sideranthus grindelioides (Nutt.) Britton. (Aplopappus Nuttallii T. 
& G.) On dry plains and hills from Ass. and Nev. to Neb. and Ariz.—Alt. 
4000-5500 ft.—Grand Junction; Rifle; Hotchkiss. 
2. Sideranthus annuus Rydb. (Aplopappus rubiginosus A. Gray; not T. 
& G.) On sandy soil from Neb. and Colo, to Kans. and Tex.—Alt. 4000- 
5000 ft.—Platte Valley, Julesburg; New Windsor; Ft. Collins. 
3. Sideranthus australis (Greene) Rydb. (Aplopappus australis Greene) 
On dry soil from Colo, to Tex. and N. M.; also in Mex.—Alt. about 4700 ft. 
—Deer Run. 
