380 CARDUACEAE. 



68. CHAMAECHAENACTIS Rydb. 



I. Chamaechaenactis scaposa (Kasfw.) Rydb. {Chacnactis scaposa Eastw.) 

 In arid regions of Utah and Colo. — Grand Junction. 



69. RYDBERGIA Greene. 



Involucres densely white-woolly at the base ; basal leaves more or less doubly 

 pinnatifid. i. 7?. grandHlora. 



Involucres darker, short-villous at the base ; leaves simply pinnatifid with few 

 divisions. 2. R. Brandegei. 



1. Rydbergia grandiflora (T. & G.) Greene. (ActincUa grandiftora T. & G.) 

 On high mountain sides from Mont, to N. M. and Calif. — Alt. 9000-13,500 

 ft. — Alpine Tunnel ; Pike's Peak ; Ironton, San Juan Co. ; Gray's Peak ; 

 Mt. Harvard; Mt. Abram. Ouray; Seven Lakes; mountains south of Ward, 

 Boulder Co. ; Little Kate Mine, La Plata Mountains ; near Pagosa Peak ; 

 Floral Mountain, near Georgetown; mountains above Como; Carson; Cam- 

 eron Pass; Berlhoud Pass; Beaver Creek; mountain northwest of Como; 

 mountains about Graymont ; Massif de I'Arapahoe; Hinsdale Co.; headwaters 

 of Clear Creek; Ethel Peak. 



2. Rydbergia Brandegei (A. Gray) Rydb. (Actinella Brandegei A. Gray; 

 Rydhej-gia glabrata Greene) On high peaks of southern Colo, and N. M. — 

 Alt. 9000-13,000 ft. — West Spanish Peak; Sierra Blanca. 



70. HYMENOXYS Cass. Colorado Rubber Plant. 



Plant low, perennial with a multicipal caudex. 



Heads mostly solitary at the ends of the branches. 



Rays 12-18 mm. long; plant 1-3 dm. high. i. H. macrantha. 



Rays 5-8 mm. long ; plant less than i dm. high. 2. //. pumila. 



Heads mostly corymbose. 



Rays orange, broadly cuneate. 3. H. Earlei. 



Rays yellow, oblong or somewhat cuneate. 4. H. floribunda. 



Plant tall, 3 dm. high or more, biennial or short-lived perennial, with one or 



few stems from a tap-root. 

 Stem simple below ; leaves pinnate or simple ; disk over i cm. wide. 



5. H. hclenioides. 

 Stem diffusely branched ; leaves once to thrice ternate ; disk 5-8 mm. wide. 



6. H. multi-flora. 



1. Hymenoxys macrantha (A. Nels.) Rydb. (Picradenia macranlha A. 

 Nels. ; H. Ricliardsonii macrantha Cockerell) In dry soil from Wyo. to Utah 

 and Colo. — Como; South Park. 



2. Hymenoxys pumila (Greene) Rydb. (Picradenia pumila Greene; H. 

 Ricliardsonii pumila Cockerell) Very dry hills from Ass. to Colo, and Utah. 

 —North Park. 



3. Hymenoxys Earlei Cockerell. In the pinon belt of Colo. — Mancos. 



4. Hymenoxys floribunda (A. Gray) Cockerell. {Actinella Ricliardsonii 

 Horibunda A. Gray; Picradenia floribunda Greene) In dry or gravelly soil 

 from Colo, to N. M. and Ariz.— Alt. 4000-10,000 ft. — Como; Buena Vista; 

 Marshall Pass ; Placer ; Westcliffe ; Twin Lakes ; Mancos ; Gunnison ; Sangre 

 de Cristo Creek; Turkey Creek and tributaries; Mt. Harvard; dry plains 

 south of Antonito ; Dillon Caiion ; Nepesta ; Colorado Springs. 



