EUPATORIACE.E. 169 



cle described as naked when the chaff is wanting: the surface of the 

 receptacle being diagnosed as alveolate, foveolale, or merely areolale, 

 according as the insertion of the achenes forms deeper or shallower 

 depressions; or fimbrillate when the receptacle around these scars rises 

 in teeth, or awns. Our largest natural order, so-called, of flowering 

 plants; the genera and species most conveniently considered under 

 subordinal, natural, by not easily definable groups. 



Rays none; style branches elongated, usually clavate-thickened upward and obtuse: 

 stigmatic only below the middle ............................ 1 . EU P ATO RI ACE.*. 



Rays usually present; anthers not caadate; style-branches of perfect flowers flattened, 

 and with a distinct terminal appendage .......................... 2. ASTER ACE^E. 



Rayb none; anthers caudate; style-branches of perfect flowers with no appendage, 

 the stigmatic lines reaching almost to the naked truncate or obtuse summit. 



Rays none; fertile fl. apetalous or nearly so; the staminate involucres forming a 

 raceme above the axillary pistillate one; pappus none ....... 4. AMBROSIACEJE. 



Rays seldom wanting; anthers not caudate; involucre not scarious; receptacle 

 chaffy; pappus never of capillary bristles ................. 5. HEI<IAXTHA<JE^E. 



Rays present, fertile, the achenes of each more or less enfolded by its involucral 

 bract; receptacle chaffy, style-branches subulate, hispid ........... 6. MAI>IACEzE. 



Rays present; receptacle naked, or merely fimbrillate; pappus paleaceous or aristi- 

 form.or when bristly rigid ................................... 7. II i: M:\ I O I I I 1 . 



Anthers not caudate; bracts of involucre more or less scarious; style-branches 

 truncate; pappus a scarious crown, or a circle of small scales, or wanting. 



........................................................... S. AUTTHEMIDE^E. 



Anthers not caudate; receptacle naked; involucres not imbricated, mostly cylin- 

 drical, the bracts not scarious; pappus of many soft-capillary bristles. 



........................................................ 9. si:\r.< IOMIM: i: 



Rays none; anthers caudate; style branches united, stigmatic to the obtuse summit, 



smooth and naked, but often with a pubescent node below; receptacle densely setose. 



................................................... 1C. CYNAROCEPHAL,^. 



Subordor 1. EUPATOKIACE^E. 



Heads rayless. Corollas all tubular and regular, never yellow, though 

 sometimes cream-color. Anthers without tails. Style branches elongated, 

 usually clavate, minutely papillose or puberulent, the stigmatic lines only 

 near the base. 



Achenes 4-angled; pappus partly squamellate ....................... TRICHOCORONIS 1 



Achenes 10-striate; pappus a single series of scabrous bristles ..... COLEOSANTHUS 2 



1. TKICHOCORONIS, A. Gray. Weak and flaccid fibrous-rooted 

 perennial of muddy shores. Leaves opposite or attenuate, sessile. 

 Heads few, peduncled, terminating somewhat corymbose branches. 

 Flowers flesh-color. Style-branches scarcely clavate; rather linear and 

 flattish. Pappus of small awns and intervening palese. 



1. T, riparia, Greene. Stems assurgent, hardly a foot high, 

 sparsely pubescent: leaves linear-lanceolate, remotely serrate, slightly 



