THISTLE FAMILY 945 



sessile, hirsutulous; heads solitary at the ends of the stem and branches; invo- 

 lucres 6 mm. high; flowers yellow, turning purplish or whitish. Dry ground: 

 Calif Ida. Wahs. Son. Mr. 



100. CHAMAECHAENACTIS Rydb. 



Cespitose scapiferous perennial, branching below the surface of the ground 

 and with a woody root. Leaves all basal and simple, coriaceous, white-strigose 

 below, sparingly hirsute and punctate above. Involucral bracts about twelve, 

 in two series, the inner series longer and with scarious-margined, recldish tips. 

 Corolla flesh-colored, with equal lobes. Stamens included. Style-tips broad. 

 Achenes clavate, densely villous. Pappus of eight nearly equal squamellae, with 

 prominent midrib and erose tips. 



1. C. scaposa (Eastw.) Rydb. Leaves petioled; blades oblong or elliptic, 

 to orbicular, 8-12 mm. long, coriaceous, entire or crenate, with revolute margins, 

 strigose-canescent; scape 3-8 cm. long; involucres about 15 mm. high and broad; 

 bracts oblong, obtuse, densely hirsute-villous. Chaenactis scaposa Eastw. 

 Actinella carnosa A. Nels. Dry mesas and clayev soil: w Colo. e Utah. My- 

 Je. 



101. CHAENACTIS DC. MORNING BRIDES. 



Annual, biennial, or perennial herbs. Leaves alternate, usually pinnately 

 dissected. Heads discoid, but the marginal flowers often with enlarged corollas. 

 Involucre campanulate or turbinate; bracts herbaceous in 2 series; receptacle 

 alveolate, naked or in some species bristly. Flowers hermaphrodite and fertile; 

 corollas yellow, white, or flesh-colored, the throat cylindric or in some species 

 funnelform in the marginal flowers. Achenes linear, terete or oval in cross- 

 section, or obscurely 4-angled, pubescent. Pappus of 4-16 hyaline squamellae. 



Annuals. 



Corollas yellow; pappus of minute callous squamellae. 1. C. Nevii. 



Corollas white or flesh-colored; pappus of well developed squamellae. 

 Stamens partly exserted; bracts all appressed. 



Involucral bracts acuminate; receptacle usually somewhat bristly. 



2. C. carphoclinia. 

 Involucral bracts obtuse or merely acute; receptacle naked. 



Leaves bipinnatifid. 3. C. stevioides. 



Leaves simple, spatulate-linear. 4. C. Cusickii. 



Stamens included; some of the outer bracts with spreading tips. 



5. C. macrantha. 

 Perennials. 



Leafy-stemmed plants. 



Plant densely white-floccose. 



Leaves mostly basal, broadly oboyate in outline, with approximate divergent 



divisions; branches of the inflorescence usually divergent at the base 



and curved upwards. 6. C. brachiata. *>*. 



Leaves scattered, ovate or lanceolate in outline; branches of the inflorescence 



ascending or erect, strict. 

 Plant 1-3 dm. high, not fruticulose; leaves regularly pinnatifld. 



7. C. achilleaefolia. 

 Plant 3-4 dm. high. 



Leaves narrow, mostly regularly pinnatifld; plant often fruticulose at 



the base. 8. C. imbricata. 



Leaves broader, interruptedly pinnatifld, with smaller segments inter- 

 posed between the larger ones; plant not fruticulose. 



9. C. cheilanthoides. 

 Plant sparingly floccose, in age greener and glabrate. 



Squamellae about half as long as the corolla; low perennials, 1-2 dm. high, 



branched at the caudex. 10. C. humilis 



Squamellae at least two-thirds as long as the corollas. 



Bracts shorter than the disk; stem 2-4 dm. high; biennials with a taproot. 



11. C. Douglasii. 

 Bracts equalling the disk; stems 1-2 dm. high, from a cespitose rootstock. 



12. C. peduncularia. 

 Subscapose perennials, with rosulate leaves and nearly naked peduncles. 



Leaves oblanceolate, elliptic, 01 linear in outline; plants with a cespitose caudex. 

 Inner bracts acuminate; leaf-blades narrowly lanceolate in outline. 



13. C. minuscula. 

 Inner bracts merely acute; leaf-blades oblanceolate or oblong in outline. 



14. C. alpina. 



Leaf-blades obovate-cuneate or flabellate in outline; plant with a cespitose root- 

 stock. 15. C. Evermannii. 



34 



