380 CARDUACEAE. 



68. CHAMAECHAENACTIS Rydb. 



I. Chamaechaenactis scaposa (Eastw.) Rydb. (Chaenactis 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- R- grandMora. 



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

 divisions. 2. R- Brandegei. 



1. Rydbergia grandiflora (T. & G.) Greene. (Actinella 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 ; Berthoud 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; 

 Rydbergia 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. z. H. pumila. 



Heads mostly corymbose. 



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



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



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. helenioides. 

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



6. H. midtiiiora, 



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

 Nels. ; H. Richardsonii macrantha Cockerel!) In dry soil from Wyo. to Utah 

 and Colo.^Como; South Park. 



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

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

 —North Park. 



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



4. Hymenoxys floribunda (A. Gray) Cockerell. (Actinella Richardsonii 

 Aoribunda 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 Cafion ; Nepesta ; Colorado Springs. 



