ANALYTICAL KEY TO THE GENERA OF THE 

 COMPOSITAE.* 



(AMBROSIACEAE, CICHORIACEAE, CARDUACEAE.) 



PREPARED BY 



DR. KARL M. WIEGAND. 



PAG 



A Flowers of the head all ligulate Family CICHORIACEAE 898 



b Pappus of scales, or of scales and bristles, or none. 



c Flowers, blue or white Cichorium 890 



cc Flowers yellow. 



d Pappus of scales, often with bristles also. 

 e Achenes truncate, i5~20-ribbed; involucre in 1-2 series. 



Adopogon (Krigia) 891 

 ee Achenes contracted into a beak, lo-ribbed; involucre in 2-4 series. 



Nothocalais (Troximori) 900 

 dd Pappus none. 



e Achenes 2o~30-nerved Lapsana 891 



ee Achenes 8-io-nerved or ribbed. 



/ Scapose plants Arnoseris 892 



// Leafy-stemmed plants Serinia 891 



bb Pappus of bristles. 

 c Bristles plumose, at least some of them. 



d Receptacle chaffy Hypochaeris 892 



dd Receptacle not chaffy. 



e Leaves linear, grass-like, cauline Tragopogon 894 



ee Leaves not grass-like; plants often scapose. 



/ Flowers pink or purple Ptiloria 894 



// Flowers yellow. 



g Plants scapose Leontodon 893 



gg Plants leafy-stemmed Picris 893 



cc Bristles simple. 

 d Achenes with spiny processes near the summit. 



e Stem branching, leafy; heads small Chondrilla 895 



ee Stem scapose; heads large, solitary Taraxacum 896 



dd Achenes smooth or merely papillose. 

 e Achenes flattened. 



/ Achenes truncate at the summit Sonchus 896 



// Achenes narrowed into a beak or neck Lactuca 897 



ee Achenes not distinctly flattened. 

 / Flowers white, cream-colored, or purple. 



g Leaves mostly linear or scale-like, often nearly wanting . Lygodesmia 899 

 gg Leaves broad, ovate to triangular or oblong . Nabalus (Prenanthes) 906 

 // Flowers yellow, orange, or flame-red. 

 g Achenes truncate or merely narrowed at the summit. 

 h Pappus bright white. 



* The names in parentheses are those used in Gray's Manual for the corresponding 

 genera, wholly or in part. 



1037 



