14 University of California Publications in Botany. [VOL. 3 



Bracts of the involucre imbricated, dry and scarious: flowers 

 white, yellow, or greenish, rays present or absent: style- 

 branches mostly truncate: pappus none or reduced to a 

 mere crown or ring 8. ANTHEMIDEAE, p. 23. 



Bracts of the involucre in 1 or 2 series, little or not at all im- 

 bricated, nor scarious: both disk and ray yellow: style- 

 branches in perfect flowers truncate: pappus of soft capil- 

 lary bristles (coarse in no. 93). ...9. SENECIONEAE, p. 24. 



Receptacle with chaffy bracts. 



Heads unisexual (except nos. 35 and 36) : anthers nearly or quite 

 distinct: rays none: corolla of perfect flowers much reduced 

 or wanting: pappus none or a mere vestige: leaves mostly 



alternate 4. AMBKOSIEAE, p. 18. 



Heads not unisexual: anthers united. 



Involucre of 1 to several series of bracts, none enfolding ray- 

 achenes: receptacle very chaffy: rays present or wanting: 



leaves mostly opposite or basal 



5. HELIANTHEAE, p. 19. 



Involucre of 1 series of equal bracts, each embracing or enfolding 

 a ray-achene: bracts of the receptacle often in a single 

 series between ray and disk: rays always present (some- 

 times inconspicuous) : leaves alternate or opposite 



6. MADIEAE, p. 20. 



Anthers caudate at the base, unappendaged at the tip: heads small: rays 

 none 3. INULEAE, p. 17. 



Anthers long-caudate at the base, with elongated appendages at the tip: 

 receptacle bristly: rays none: leaves alternate: spiny thistles or 

 thistle-like plants 10. CYNAEEAE, p. 24. 



B. Corollas all bilabiate and the flowers all perfect 



11. MUTISIEAE, p. 25. 



C. Corollas all ligulate and the flowers all perfect: anthers not caudate: 



herbage with milky juice: leaves alternate or basal 



....12. CICHOKIEAE, p. 25. 



TRIBE 1. EUPATORIEAE. EUPATORY TRIBE. 



Herbs and shrubs with opposite or alternate mostly undivided 

 leaves. Receptacle flat or somewhat convex, rarely spherical, 

 usually naked. Heads always discoid and the flowers herma- 

 phrodite-fertile. Corolla regular, purple reddish bluish or white, 

 never pure yellow. Anthers not tailed at base. Style-branches 

 semi-cylindric, elongated, more or less clavate or thickened up- 

 ward, obtuse, stigmatic lines only near the base and incon- 

 spicuous. 



