STANDLEY TEEES AND SHRUBS OF MEXICO 1403 



Tribe I. Vernonieae. 

 Pappus double, the outer series short, subpaleaceous or rarely setose, the inner 



much longer, setose 1, VERNONIA. 



Pappus (in our species) a low entire crown 2. OLIGANTHES. 



Tribe II. Eupatorieae. 

 Pappus none, or a very short crown. 



Heads 3-flowered (in our species) ; anthers unappendaged at apex. 



3. PIQUEBIA. 

 Heads several to many-flowered; anthers appendaged at apex. 



Achenes compressed 7. O AXAC ANIA. 



Achenes prismatic, 4 or 5-angled. 



Achenes 4-angled 6. JALISC O A. 



Achenes 5-angled. 



Pappus entirely wanting 5. ALOMIA. 



Pappus a low paleaceous crown 9. AGERATUM. 



Pappus present, better developed. 



Achenes prismatic and 8 to 10-ribbed, or obovoid and not distinctly ribbed. 

 Achenes prismatic, 8 to 10-ribbed; receptacle naked. 



Pappus of 4 to 14 linear-attenuate scarious-margined awns; phyllaries few, 



unequal, subherbaceous 19. CARPHOCHAETE. 



Pappus of numerous bristles; phyllaries usually multiseriate, dry and 



striate 20. COLEOSANTHUS. 



Achenes obovoid, not distinctly ribbed; receptacle paleaceous. 



21. DYSCRITOTHAMNUS. 

 Achenes 4 or 5-ribbed (rarely 2 or 3-ribbed). 

 Pappus of bristles only. 



Phyllaries 4; heads 4-flowered 18. MIKANIA. 



Phyllaries and flowers more numerous. 



Pappus bristles deciduous 15. PIPTOTHRIX. 



Pappus bristles persistent. 



Anthers without terminal appendage. 



Pappus bristles dilated at tip 4. DECACHAETA. 



Pappus bristles not dilated at tip 17. OPHRYOSPORUS. 



Anthers with terminal appendage. 



Pappus bristles few (5 to 8) 14. FLEISCHMANNIA. 



Pappus bristles numerous 16. EUPATORIUM. 



Pappus at least in part of squamellae or awns. 



Phyllaries 5 to 8, uniseriate, subequal 12. STEVIA. 



Phyllaries more numerous. 



Anthers unappendaged at apex; pappus of 5 squamellae prolonged into 



awns 11- AGERATELLA. 



Anthers appendaged at apex; pappus otherwise. 



Pappus of 2 to 10 bristles and a few squamellae; involucre strongly 

 graduate. 

 Squamellae of pappus evident, paleaceous or scarious. 



13. HOFMEISTERIA. 



Squamellae of pappus minute, setulose--14. FLEISCHMANNIA. 



Pappus of squamellae only, these sometimes united into a paleaceous 



crown. 



Involucre strongly graduate; pappus of about 15 membranaceous 



squamellae 8. ASCHENBORNIA. 



Involucre subequal; pappus of 5 to 10 squamellae, or these united 

 into a crown. 



