1907] Hall. Compositae of Southern California. 19 



All but uppermost leaves pinnately parted: aehenes villous 



36. OXYTENIA, p. 117 



Aehenes with a scarious pectinate border or wing....37. DICORIA, p. 117. 

 Heads unisexual, staminate and pistillate heads on the same plant; involucre 

 of pistillate heads closed, only the style-branches exserted; staminate 

 heads with open involucres. 



Involucre of pistillate heads with broad silvery-scarious wings 



38. HYMENOCLEA, p. 118. 



Involucre of pistillate heads bur-like. 



Staminate heads with united involucral bracts. 



Pistillate involucre beaked at apex and armed near the beak with 



a single row of short prickles 39. AMBEOSIA, p. 119. 



Pistillate involucre with 1 to 4 beaks and armed with several 



rows of prickles 40. FRANSEEIA, p. 120. 



Staminate heads with distinct involucral bracts 



- 41. XANTHIUM, p. 123. 



TRIBE 5. HELIANTHEAE. SUNFLOWER TRIBE. 



Herbs or shrubs with mostly yellow flowers, many with bal- 

 samic-resinous juice. Heads homogamous and discoid or heter- 

 ogamous with pistillate or neutral ray-flowers and hermaphrodite 

 disk-flowers, the latter either fertile or sterile. Eeceptacle with 

 chaff-like bracts, each subtending a flower. Anthers obtuse at 

 base, not caudate. Pappus various or wanting but never of 

 simple truly capillary bristles. Aehenes thick or flattened con- 

 trary to the subtending chaffy bract, never parallel with it. 



A. Involucre either imbricated or its outer bracts foliaceous and ex- 

 ceeding the inner ones. 



Disk-achenes thick, 4 or 5-angled when mature. 

 Rays small and white or wanting. 



Pappus of 15 to 20 plumose bristles: heads discoid 



42. BEBBIA, p. 125. 



Pappus paleaceous: rays white 43. GALINSOGA, p. 126. 



Pappus of barbed awns: rays white or none 51. BIDENS, p. 143. 



Rays conspicuous, yellow. 

 Pappus none. 



Leaves scattered, narrow (1 cm. or less broad) 



GYMNOLOMIA, p. 145. 



Leaves mainly basal, ample (8 to 15 cm. broad) 



44. BALSAMORHIZA, p. 126. 



O r - THE 



UNIVERSITY 



