1907] Hall. Compositae of Southern California. 149 



thick and turgid (never laterally compressed with narrow back), 

 each partially enclosed by the lower part of its involucral bract. 

 Disk-achenes sterile. 



A. Receptacle with a cup-like circle of bracts between disk and ray: 

 leaves (never spinose) destitute of truncate glands. 



Pappus none: flowers yellow. 



Leaves entire 1. H. Wheeleri. 



Lower leaves pinnately divided 3. H. corymbosa. 



Pappus of disk-achenes present. 



Flowers yellow: leaves linear or broader. 



Eays 8 to 20: disk-flow r ers as many or more. 



Perennial: herbage not glandular: insular 2. H. Clementina. 



Annuals: at least the involucres glandular. 



Disk-achenes wholly sterile and with pappus of minute fimbri- 



ate scales or wanting 3. H. cormybosa. 



Disk-achenes well formed and with pappus of oblong obtuse 



pubescent or erose paleae. 

 Beak of ray-achenes curved: some of the cauline leaves 



pinnatifid 4. H. paniculata* 



Beak of ray-achenes straight : cauline leaves all entire 



5. H. floribunda. 



Bays mostly 5 (3 to 8) : disk-flowers not over 10. 



Involucral bracts not carinate: heads on slender peduncles 



6. H. Wrightii. 



Involucral bracts carinate: heads mostly in small clusters 



7. H. fasciculata. 



Flowers white: leaves nearly filiform 8. H. tenella. 



B. Receptacle with chaffy bracts throughout; no cup-like circle between 



disk and ray: flowers yellow. 

 Leaves not spinose, the uppermost ones tipped with a truncate gland. 



Eays 4 or 5: leaves crowded on the branchlets 9. H. virgata. 



Eays 5 to 8 : leaves scattered on the branchlets 10. H. Heermanni. 



Leaves spinose and rigid (at least the upper) : rays 25 to 40, 2-lobed. 



Disk-pappus of 3 to 5 entire paleae or wanting 11. H. pungens. 



Disk-pappus of 8 to 12 paleae, fimbriate at the tip 12. H. FitcJiii. 



1. H. Wheeled Gray, Bot. Calif, i. 617 (1876)- Madia tenella 

 Greene, Pitt. iii. 167 (1897). 



Slender, erect, 1.5 to 6 dm. high: stem simple or branching 

 below, more or less cymosely branched above and bearing scat- 

 tered heads of bright-yellow flowers ; the cymes sometimes con-' 

 densed (simple-stemmed and monocephalous only in depauperate 

 plants) : herbage hirsute with spreading white hairs, the inflor- 

 escence glandular: leaves scattered (the lower opposite, the upper 



