350 



COMPOSITAE. 



517. 



511. 



Pappus of rigid backward ly- 



barbed awns. 515. 



Pappus not of backwardly- 



barbed awns. 



Pappus of numerous sep- 

 arate short rigid or 

 chaffy bristles. 

 Pappus none or a minute 



crown. 



Involucre scarious. 530. 

 Involucre not scarious. 

 Heads solitary. 

 Heads in clusters. 

 Disk-flowers 1- 



5. 

 Disk-flowers 



numerous. 540. 



Ray-flowers present, at least some of the 

 marginal flowers having strap-shaped 

 corollas. 

 Pappus none. 



Involucre scarious. 

 Receptacle naked. 

 Receptacle chaffy. 



Involucre narrow; rays short. 

 Involucre broad; rays con- 

 spicuous. 

 Involucre not scarious. 



Akenes all laterally compressed. 

 Akenes or at least part of them 



turgid or obcom pressed. 

 Tegules not at all enclosing 



the ray akenes. 

 Tegules at least partly enclos- 

 ing the ray akenes. 

 Ray akenes turgid, partly 



enclosed by the tegules. 

 Ray akenes usually ob- 

 compressed, wholly 

 enclosed by the te- 

 gules. 



Ray akenes straight, 

 each enclosed by the 

 basal part of the 

 tegule. 



Ray akenes curved, 

 each enclosed by the 

 whole tegule. 

 Pappus present, at least in the disk- 

 flowers. 



Pappus not of capillary bristles. 

 Receptacle chaffy. 



Pappus of scales or awns. 

 Awns 2, or 4, retrorsely 



barbed. 515. 



Awns 2, barbless. 516. 



Pappus crown-like or of 



BIDENS, 374. 



549. ARCTIUM, 395. 



529. 

 527. 

 528. 

 511. 



MATRICARIA, 380. 

 RUDBECKIA, 375. 



MADIA, 372. 

 PSILOCARPHUS, 390. 



CHRYSANTHEMUM, 380. 

 ACHILLEA, 379. 

 ANTHEMIS, 379. 

 MADIA, 372. 



518. BALSAMORRHIZA, 376. 



513. HEMIZONIA, 374. 



514. 



512. 



LAGOPHYLLA, 374. 

 HEMIZONELLA, 374. 



BIDENS, 374. 

 COREOPSIS, 375. 



