244 COMPOSITAE. 



Pappus not of separate capillary 



bristles. 

 Pappus of numerous bristles 



united into a ring at the base. 387. CIRSIUM, 259. 

 Pappus not of bristles united into 



a ring. 

 Pappus of rigid backwardly- ' 



barbed awns. 411. BIDENS, 276. 



Pappus not of backwardly- 



barbed awns. 

 Pappus of hyaline or chaffy 



scales. 388. CHAENACTIS, 261. 



Pappus none or a minute 



crown. 



Involucre scarious. 389. MATRICARIA, 261. 

 Involucre not scarious. 



Heads solitary. 390. RUDBECKIA, 26i. 

 Heads in clusters. 



Disk flowers 1-5. 395. MADIA, 263. 

 Disk flowers nu- 

 merous. 391. PSILOCARPHUS, 262. 

 Ray flowers present, at least some of the 

 marginal flowers having strap-shaped 

 P corollas. 

 Pappusjnone. 



Involucre scarious. 



Receptacle naked. 392. CHRYSANTHEMUM, 262. 



Receptacle chaffy. 



Involucre narrow; rays short. 393. ACHILLEA, 262. 

 Involucre broad; rays conspi- 

 cuous. 394. ANTHEMIS, 263. 

 Involucre not scarious. 



Akenes all laterally compressed. 395 MADIA, 263. 

 Akenes or at least part of them 



turgid or obcompressed. 

 Involucral bracts not at all 



enclosing the ray akenes. 396. BALSAMORHIZA, 264. 

 Involucral bracts at least 

 partly enclosing the ray 

 akenes. 



Ray akenes turgid, each 

 partly enclosed by the 



involucral bract. 397. HEMIZONIA, 264. 



Ray akenes usually ob- 

 compressed, each wholly 

 enclosed by the base of 



the involucral bract. 398. LAGOPHYLLA, 265. 

 Pappus present, at least in the disk 



flowers. 



Pappus of capillary bristles. 

 Ray flowers not yellow. 



Low shrub. 399. ERICAMER1A, 265. 



Herbs, woody only at the base. 

 Bracts of the involucre in 

 many series, their tips 



spreading. 400. MACHAERANTHERA, 265. 



Bracts of the involucre in 

 1-5 series, their tips 

 erect. 



