402 THE KINDS OF PLANTS 



cccc. Pappus of luauy bristles. 



D. Plant very prickly 22. Cnicus 



DD. Plant not prickly. 



E. Involucre prickly and bur-like 23. Arcthim 



EE. Involucre not bur-like or prickly. 



F. Torus bristly (chaff or bracts amongst 



the florets) 24, Centaurea 



FF. Torus naked. 



G. Rays present. 

 H. Flowers yellow. 



I. Leaves all radical : rays 



numerous and fertile ..25. Tiissilago 

 II. Leaves on stems, alternate. 

 J. Heads small, in large 



clusters or panicles. 26. Solidago 

 jj. Heads large and broad: 

 leaves large on stem 

 and in a basal clump. 27. Inula 

 HH. Flowers not yellow. 



I. Scales of the involucre un- 

 equal 28. Aster 



II. Scales equal in length 29. £rigeron 



III. Scales in several rows, more 



or less leafy 30. CaUistephtts 



GG. Rays none. 



H. Plants cottony-white, or downy- 

 looking. 

 I. Heads mostly dicecious. 

 J. Leaves basal and also on 

 stem: pappus thick- 

 ened at sun)mit and 

 more or less barbed 



or plumed ..31. Antennaria 



JJ. Stems leafy: pappus not 

 thickened at summit : 

 some sterile flowers, 

 usually in center of 



the fertile heads 32. Anaphalis 



n. Heads not dioecious: outer 

 flowers pistillate, central 



perfect 33. Onaphalium 



HH. Plants not cottony-white. 



I. Flower -heads showy, spi- 

 cate or racemed, rose- 

 purple: leaves alter- 

 nate 34. Liatris 



