THISTLE FAMILY 951 



glabriuscula Rydb. A. epunctata A. Nels. Dry hills: Colo. N.M. Utah. 

 Submont. Mont. Je-Jl. 



12. T. angustifolia Rydb. Leaves narrowly linear-oblanceolate, 4-10 cm. 

 long, 4-5 mm. wide, loosely and sparingly long-villous, or glabrate in age; scape 

 2-3 dm. high, strigose; involucre hemispherical, 10-12 mm. wide; bracts oblong, 

 obtuse, densely villous; ligules about 1 cm. long; pappus-squamellae ovate, 

 acuminate. Dry rocky hills: Colo. Tex. N.M. Plain Submont. Mr-O. 



13. T. fastigiata Greene. Leaves basal, very narrowly linear-oblanceolate, 

 2-4 cm. long, 1-2 mm. wide, strongly punctate, glabrous or with a few long hairs 

 near the base; scape 5-10 cm. long, striate, punctate and sparingly strigose; 

 involucre about 5 mm. high and 10 mm. wide, hemispheric; bracts elliptic, ob- 

 tuse; ligules light yellow, about 10 mm. long and 5 mm. wide; pappus-squamellae 

 ovate, acuminate. T. slenophylla Rydb. A. fastigiata A. Nels. Dry plains: 

 Kans. Colo. Tex. Plain. My-Jl. 



14. T. leptoclada (A. Gray) Greene. Stem 1-3 dm. high, sparingly ap- 

 pressed-pubescent; basal leaves glabrate or slightly hairy, hairy- tufted at the 

 base, 3-6 cm. long, 4-6 mm. wide; stem-leaves linear, few; involucres 7-8 mm. 

 high, 12-15 mm. broad, more or less villous; outer bracts oblong, lanceolate or 

 linear, the inner elliptic, oval, or somewhat qbovate, rounded; ligules 8-10 mm. 

 long; pappus-squamellae ovate, gradually aristate. A. leptoclada A. Gray. T. 

 mancosana A. Nels. T. intermedia Greene, a form with somewhat narrow 

 bracts. Dry hills: Colo. N.M. Utah. Submont. Mont. Ap-Jl. 



15. T. Ivesiana Greene. Stem 1-3 dm. high, sparingly pubescent; leaves 

 all narrowly linear or lance-linear, 5-10 cm. long, 1-4 mm. wide, erect; involucre 

 somewhat turbinate, 5-6 mm. high, 7-8 mm. broad, silky-villous ; bracts elliptic, 

 obtuse; ligules about 10 mm. long, strongly veined; squamellae lanceolate, 

 acuminate into an awn. Canons and hillsides: Utah Ariz. N.M. Son. 



106. RYDBERGIA Greene. 



Stout caulescent perennials with taproots. Leaves alternate, once or twice 

 ternately or quinately divided into linear divisions, or some of them entire. 

 Heads radiate, solitary. Involucre depressed-hemispheric; bracts in about 3 

 series, linear, distinct, subequal or the inner shorter, densely woolly. Recep- 

 tacle convex or hemispheric, naked. Ray-flowers 15-30, pistillate, fertile; lig- 

 ules yellow, elongate, 3-toothed. Disk-flowers numerous, hermaphrodite and 

 fertile. Style-tips truncate, penicillate* Achenes obpyramidal, silky-hirsute, 

 5-angled. Pappus of 5 lance-subulate or linear-lanceolate attenuate squamellae 

 with faint midrib. 



Basal leaves all dissected; plant villous. 1. R. grandi flora. 



Basal leaves, at least some of them, simple; plant more glabrate. 2. R. Brandegei. 



1. R. grandiflora (T. & G.) Greene. Stem 1-3 dm. high, stout, floccose, 

 leafy; leaves once or twice pinnatifid with linear lobes, more or less floccose; invo- 

 lucres 2-4 cm. broad, densely white-woolly; ligules 1-5-2 cm. long, 4-5 mm. 

 broad. Actinella grandiflora T. & G. High mountain sides: Mont. N.M. 

 Utah. Mont. Alp. Jl-Au. 



2. R. Brandegei (A. Gray) Rydb. Stem short-villous above, glabrate 

 below, almost scapiform, 1-2 dm. high; leaves pinnatifid, with a few linear lobes 

 or entire and linear, glabrate; involucre 2-3 cm. wide, dark, short villous; ligules 

 8-10 cm. long and 4 mm. wide. A. Brandegei A. Gray. R. glabrata (Porter) 

 Greene. High mountains: Colo. N.M. Mont. Alp. Jl-Au. 



107. HYMENOXYS Cass. COLORADO RUBBER PLANT. 



Caulescent annuals, biennials, or perennials. Leaves alternate, commonly 

 pinnatifid into narrowly linear divisions. Heads (in ours) radiate. Involucre 

 of two series of bracts, 5-16 in each series, the outer usually narrower and more 

 or less united at the base, rather firm, entire, acute, the inner broader, either 

 similar, or else more or less erose on the margin and abruptly acuminate or 



