47 



COMPOSITAE (COMPOSITE FAMILY) 



Involucral bracts in more than two rows. 



Involucral bracts herbaceous or at least green-tipped. 

 Lobes or teeth of the leaves mucronate or bristle- 

 tipped. 

 Involucral bracts in several series, usually recurved or 



reflexed . . 



Involucral bracts in 2-3 series, loose but not reflexed 

 Lobes or teeth of the leaves not mucronate or bristle- 

 tippsd; involucral bracts often spreading, but not 

 recurved or reflexed. 

 Disk-flowers turning brown or reddish. 



Stems usually branching, and the heads several- 

 many ........ 



Stems low, monocephalous; dwarf alpines. 

 Stems scapose . . . . 



Stems leafy . . . . . . 



Disk-flowers permanently -white .... 



Bracts not foliaceous or noticeably green-tipped 

 Involucral bracts in 1 or 2 rows ..... 



Rays inconspicuous or wanting. 



Annuals, with numerous small heads and rays not longer 

 than the pappus ....... 



Perennials (shrubs); rays wanting 



23. Machaeranthera. 

 21. Xylorhiza. 



22. Aster. 



24. Oreastrum. 



25. lonactis. 



26. Leucelene. 

 28. Wyomingia. 



27. Erigeron. 



29. Leptilon. 



30. Baccharis. 



Tribe IV. INULEAE 



Receptacle chaffy; stigmas of hermaphrodite flowers not truncate . 

 Receptacle not chaffy; stigmas of hermaphrodite flowers truncate. 



Plants dioecious or polygamo-dioecious. 

 Pappus of staminate flowers clavate 

 Pappus alike in all the flowers 



Plants not dioecious; all the flowers fertile. 

 All the flowers hermaphrodite 

 Only the inner flowers hermaphrodite 



31. Filago. 



32. Antennaria. 



33. Anaphalis. 



34. Nacrea. 



35. Gnaphalium. 



Tribe V. HELIANTHEAE 



Involucral bracts not inclosing the ray achenes; herbage not glan- 



dular viscid. 

 Ray-flowers fertile and ligulate; disk-flowers sterile. 



Ligules conspicuous ........ 



Ligules reduced to 2 or 3 teeth or wholly wanting. 



Caulescent annual ........ 



Acaulescent perennial ........ 



Disk-flowers fertile; rays, if present, fertile or sterile. 

 Stamens distinct. 



Heads with both staminate and pistillate flowers. 



Involucral bracts acuminate ...... 



Involucral bracts obtuse. 

 ' Fertile flowers more than one . . . . . 



Fertile flower solitary ....... 



Heads unisexual; pistillate heads usually spiny. 



Bracts of the staminate heads separate; pistillate head 

 forming an oblong bur ...... 



Bracts of the staminate heads united. 



Pistillate flowers solitary in each head; spines in a single 

 series ......... 



Pistillate flowers 1-4 in each head; spines in several 

 series ......... 



Stamens syngenesious. 



Achenes compressed; leaves entire . . . . 



Achenes 4-sided; leaves toothed . . : . 

 Ligules deciduous or wanting. 



Receptacle high-conical or cylindrical. 

 Rays pistillate, sterile. 



Ligules rose-colored ...... 



Ligules yellow ....... 



Rays neutral. 



Achenes 4-sided, marginless ..... 



Achenes flattened laterally and margined . . 



Receptacle flat to convex. 



Achenes not winged or very flat. 



Pappus wanting ....... 



Pappus present (a laciniate crown or distinct scales). 



Pappus coroniform and persistent . . . 



Pappus of 2-pointed very deciduous scales . . 



Achenes flat, winged or wingless (terete in No. 58), usu- 



ally 2-3-awned. 



36. Melampodium. 



37. Parthenice. 



38. Bolophyta. 



39. Oxytenia. 



40. Iva. 



41. Dicoria. 



44. Xanthium. 



42. Ambrosia. 



43. Franseria. 



45. Crassina. 



46. Heliopsis. 



47. Brauneria. 



48. Gymnolomia. 



49. Rudbeckia. 

 60. Ratibida. 



51. Balsamorrhiza. 



52. Wyethia. 



53. Helianthus. 



