1 . VBRNONIA Sohreb. Ironweed. 



Leaves alternate. Heads oymose-paniculate, many-flowered. Flowers 



purple. 



Bracts of involucre with filiform tips. 1. V. crinita. 

 Bracts of involucre not filiform-tipped. 



Leaves linear-lauceolate. 2. V. fasciculata. 

 Leaves lanceolate to ovate- lanceolate. 



Leaves little pubescent beneath. 3. V. maxima. 



Leaves strongly pubescent beneath. 4. V. interior. 



1. V. crinita Raf. 4°-8° high, glabrate to downy : leaves lanceolate, 

 dentate to denticulate : heads 50-70- flowered. — One clump on the prairie 

 near Waldo Park. Probably a waif. July-October. 



2. V. fasciculata Miohx. 3°-7° high, pubescent or glabrate : leaves 

 linear-lanceolate, finely serrate, thick, W-9f' broad : heads 20-30-flow- 

 ered, 2" broad : scales acute or obtuse, appressed. — Occasional in low 

 grounds throughout, but abundant in the northeastern part. August- 

 October. 



3. V. mazima Small. 4°-10° high, pubescent or glabrate : leaves 

 lanceolate, sharply serrate, thin, broader than the last : heads like the 

 last, but scales acute to muoronate. — In low grounds especially along the 

 Missouri Eiver. Possibly only a low ground form of the next. July- 

 October. 



4. V. Interior Small. Resembles number 3, but leaves usually densely 

 pubescent beneath : heads 3" broad : involucral scales appressed. — Abun- 

 dant in dry grounds throughout. June-October. Our most common 

 species. 



Var. Drummondil (Shuttlw. ) Mackenzie & Bush, n. comb. Heads 

 4//_g// broad. — Common in dry grounds especially in the southern part. 

 ( V. Drummondi Shuttlw. ) 



Var. Baldwinii (Torr. ) Mackenzie & Bush, n. comb. Heads 3" 

 broad : scales of involucre spreading or recurved. — Dry woods at Swope 

 Park. Not common. {V. Baldwinii Ton.) 



2. ELEFHANTOFUS L. 

 Heads 2-5-flowered, several together forming bracted glomerules. 

 Pappus of a few awn-like bristles. 



