76 University of California Publications in Botany. [ VOL - 



22. ASTER L. ASTER. 



Late-aestival or autumnal herbs or rarely shrubs, with alter- 

 nate leaves and commonly showy heads. Inflorescence various. 

 Heads heterogamous with usually fertile ray-flowers, or homo- 

 gamous through the deficiency of rays. Involucre turbinate or 

 campanulate to hemispheric, the bracts imbricated in several 

 ranks. Disk-corollas yellow, changing to purple or brown, tubu- 

 lar, the limb shortly 5-toothed. Receptacle plane or convex, 

 pitted. Style-branches flattened, their appendages subulate or 

 lanceolate and acute. Achenes compressed. Pappus copious, of 

 simple capillary bristles. 



A. Perennials: tips of involucral bracts erect: herbage pubescent except 

 in nos. 2, 12, 13, and 14. 



Pappus of coarse rigid bristles: desert species with woody stems and large 

 solitary heads. 



Leaves acuminate: peduncles elongated 1. A. tortifolius. 



Leaves obtuse: peduncles short 2. A. Orcuttii. 



Pappus fine and soft. 



Eays conspicuous: stems herbaceous. 



Stems leafy (leaves early deciduous in no. 5) : polycephalous except 



in forms of no. 11. 

 Involucral bracts with broad green tips, closely imbricated. 



Inflorescence distinctly cymose: insular species with coriaceous 



leaves 3. A. radulinus. 



Inflorescence .racemose or paniculate. 



Plants over 35 cm. high: foothills and valleys. 



Herbage rough-pubescent or almost glabrous: inflores- 

 cence mostly condensed: leaves rigid 



4. A. Menziesii. 



Herbage soft-pubescent or glabrous : inflorescence mostly 



rather loose. 

 Eameal leaves linear, 6 mm. or less wide. 



Inflorescence with minute rigid bracts (these 5 



mm. long) 5. A. defoliatus. 



Inflorescence leafy-bracteate ...6. A. Bernardinus. 



Eameal leaves lanceolate, mostly 8 to 20 mm. wide 



7. A. CMlensis. 



Plant 15 to 30 cm. high: mountains above 1200 m. : var. 

 Parishii of.... ....10. A. Fremonti. 



