WOOTON AND STANDLEY FLOEA OF NEW MEXICO. 637 



144. ASTERACEAE. Aster Family. 



Annual or perennial herbs or low shrubs with opposite or alternate leaves; flowers 

 aggregated on a naked or scaly receptacle, surrounded by an involucre; involucre 

 of distinct or partly united bracts in one or more series; calyx of bristles, awns, or 

 scales or cuplike, forming pappua at maturity, sometimes wanting; corolla 5-lobed, 

 that of the marginal flowers often produced into a ray; ovary 1-celled; stigmas 2; 

 fruit an achene. 



KEY TO THE TRIBES. 



Stigma tic lines at the base of the stigmas or below the middle; heads discoid, never 

 yellow nor brown; anthers not caudate at the base. 

 Stigmas filiform or subulate, hispidalous; coarse perennial herbs with corym- 

 bose purple heads I. VERNONIEAE (p. 637). 



Stigmas more or less clavate, papillose-puberulent ; habit various. 



n. EUPATORIEAE (p. 637). 



Stigmatic lines extending to the tips of the stigmas or their appendages; heads discoid 



or radiate, variously colored; anthers sometimes caudate at the base. 



Anther sacs caudate at the base; heads never radiate; corollas yellow only in a 



few species of Cirsium. 



Anthers not appendaged at the top; heads heterogamous or dioecious; pistillate 



flowers with filiform corollas; mostly small whitish plants with very 



small heads IV. GNAPHALIEAE (p. 640). 



Anthers with elongate, cartilaginous, mostly caudate appendages at the top; 

 flowers all perfect or the marginal neutral; corolla not filiform; coarse 

 plants with large heads and often spiny leaves. 



IX. CYNAREAE (p. 645). 



Anther sacs not caudate at the base; heads commonly radiate and with yellow 



or brown disk flowers. 



Stigmas of the perfect flowers with more or less distinct appendages, these 



usually strongly hairy outside, glabrous inside, but never with a ring of 



longer liairs m. ASTEREAE (p. 638). 



Stigmas of the perfect flowers without appendages or these, if present, hairy 

 on both sides and with a ring of longer hairs. 

 Pappus capillary; stigmas often appendaged. 



Vm. SENECIONEAE (p. 645). 

 Pappus never capillary; stigmas rarely appendaged. 



Bracts of the involucres dry and scarious; rays mostly white or 



inconspicuous VU. ANTHEMIDEAE (p. 645). 



Bracts of the involucres herbaceous or foliaceous; raya various. 

 Receptacle with chaffy scales subtending the flowers. 



V. HELIANTHEAE (p. 641). 



Receptacle naked or in Gaillardia with bristles, never chaffy- 



bracted VI. HELENIEAE (p. 643). 



KEY TO THE GENERA. 



Tribe I. VERNONIEAE. 

 A single genus 1. Vernonia (p. 645). 



Tribe II. EUPATORIEAE. 



Achenes 5-angled, destitute of intervening ribs. 

 Pappus wholly of capillary bristles. 



Annuals; jiappus bristles plumose 2. Carminatia (p. 646). 



