i78 



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 

 Lobesior teeth of the leaves not mucronate or bristle- 

 I tipped; involucral bracts often spreading, but not 



: > recurved or reflexed. 



i .V. ; ( Disk-flowers turning brown or reddish. 



Stem" .liuaiiy branching, and the heads several- 

 many 



Stems low, monocephalous; dwarf alpines. 



Stems scapose 



Stems leafy . . ^ 



Diak-flv-M >rs permanently white .... 

 Bracts nut foliaceous or noticeably green-tipped 



Involucral bracts in 1 or 2 rows 



Hays 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. 

 26. lonactis. 



26. Leucelene. 

 28. W^omingia. 



27. Engeron. 



29. Leptilon. 



30. Bacchaiis. 



Tribe IV. IHULEAE 



Receptacle chaffy; stigmas of hermaphrodite flowers not truncate 

 Receptacle not chaffy; stigmas of hermaphrodite flowers trimcate, 

 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. 



36. Gnaphalium. 



Tribe V. HELIANTHEAE 



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

 dmar viscid. '' 

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



Ligules conspicuous . ... . . . . 



Ligules reduced to 2 or 3 teeth or whollj^ 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 , - , « 



I 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 



36. Melampodium. 



37. Parthenice. 



38. Bolophyta. 



39. Ozytenia. 



40. Iva. 



41. Dicciria. 



44. Zanthium. 



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



Stamens syngenesious. 

 ,Ligules persistent and becoming papery. 

 . Achenes compressed; leaves entu-e .... 



' Achenes 4-sided; leaves toothed 



Ligules deciduous or wanting. 

 Receptacle high-conical or cylindrical. 

 R^p^s pistillate, sterile, 



Ligules rose-colored 



Ligules yellow 



Rays neutral. 



Achenes 4-sided, marginless ..... 

 Achen^ 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, 



42. Ambrosia. 



43. Franseria. 



46. Crassina. 

 46. Heliopsis. 



47, Brauneria. 



48. Gymnolomia. 



49. Rudbeckia. 

 60. Ratibida. 



61. Balsamorrhiza 



62. Wyethia. 



63. Helianthui. 



