ANALYTICAL KEY TO GENERA OF COMPOSITAE. 



PAGB 



g Receptacle conic. Matricaria 1015 



gg Receptacle flat or convex. 

 h Heads corymbose; pappus a short crown. 



i Leaves serrate Chrysanthemum 1014 



ii Leaves i-3-pinnately dissected or divided Tanacetum 1016 



hh Heads paniculate-racemose or spicate; pappus none. 



i Leaves deltoid, undivided Adenocaulon 979 



ii Leaves lanceolate, linear or pinnatifid Artemisia 1017 



dddd Pappus capillary. 



e Receptacle chaffy; white-woolly herbs Gifola (Filago) 972 



ee Receptacle not chaffy, sometimes bristly. 



/ Involucral bracts white -scarious, in several series; white-woolly herbs. 

 g Basal leaves larger than, and differing from, the cauline; dioecious 



herbs Antennaria 973 



gg Basal leaves nearly similar to the cauiine or wanting. 

 h Involucre papery-white, spreading; plants dioecious . . . .Anaphalis 976 

 hh Involucre appressed, yellow, whitish, purple, or brown; plants not 



dioecious. 

 i Heads narrow, 5-7-flowered; bright yellow; corolla large. 



Chrysothamnus (Bigelovia) 931 

 ii Heads broader, many-flowered, not bright yellow; corollas small. 



Gnaph a Hum 977 

 // Involucral bracts not scarious, or only at the tip, or if entirely so 



plant not white-woolly. 

 g Flowers yellow or yellowish -cream color. 

 h Involucral bracts in one series, often with minute ones at the base. 



* Flowers cream -color Erechthites 1023 



ii Flowers bright yellow Senecio' 1024 



hh Involucral bracts imbricated in several series. 

 i Leaves spiny or spinulose-dentate. 



j Heads 3-10 cm. broad Carduus (Cnicus) 1030 



jj Heads 12-30 mm. broad Sideranthus (in Aplopappus) 932 



ii Leaves not spiny. 

 / Shrubby at least at the base. 



k Dioecious; glabrous or glutinous Baccharis 971 



kk Flowers perfect; plants white-woolly when young. 



Chrysothamnus (in Bigelovia) 931 

 jj Herbaceous. 



k Involucre glutinous; eastern Chondrophora (in Bigelovia} 930 



kk Involucre not glutinous; western Oonopsis (in Bigelovia} 931 



gg Flowers purple, violet, or white. 

 h Involucral bracts in i series, often with minute bracts at the base. 



i Climbing plants Willugbaeya (Mikania) 924 



ii Not climbing. 



j Leaves all basal Petasites 1021 



jj Leaves cauline. 

 k Leaves lanceolate or ovate-lanceolate, tapering gradually toward 



the base Erechthites 1023 



kk Leaves oval, reniform or hastate-lanceolate. 



/ Involucre of about 5 bracts Mesadenia (in Cacalid) 1023 



// Involucre of about 12 bracts Synosma (in Cacalia) 1024 



hh Involucral bracts in 2 -many series. 



* Foliage spiny. 



j Receptacle densely bristly. 



k Filaments separate Carduus (Cnicus} 1030 



kk Filaments united below Mariana (Silybum) 1034 



jj Receptacle not bristly Onopordon 1034 



ii Foliage not spiny. 



j Shrubby plants; dioecious. ......................... Baccharis 971 



7; Herbs j not dioecious. 



