904 Compositae Vernonia 



Achenes columnar, often slender. 



Flowers cream color, whitish, or pale purplish; heads pendulous 



9606. Prenanthes, p. 1014. 



Flowers yellow or reddish; heads erect. 



Achenes beaked 9604. Pyrrhopappus, p. 1013. 



Achenes not beaked. 



Pappus white 9605. Crepis, p. 1013. 



Pappus tawny 9607. Hieracium, p. 1016. 



8751. VERNONIA Schreb. Ironweed 



Note : The Indiana ironweeds are difficult to separate into species because 

 there are so many intergrading forms, which are due, possibly, to hybridi- 

 zation. My study was made with a lens of 28 diameter magnification and 

 was restricted to my 123 specimens from Indiana. Duplicates of most of my 

 specimens have been seen by H. A. Gleason, who revised the genus (North 

 Amer. Flora 33 : 32-95. 1922) and he writes that Indiana has only the 

 three species. 



Under surface of leaves (except the midrib and principal veins which are usually more 

 or less pubescent) subglabrous to minutely pubescent with one-celled, conical hairs, 

 the hairs more or less appressed. 

 Inflorescence paniculate, the branches widely spreading; under surface of leaves not 



punctate, rarely specimens more or less punctate 1. V. altissima. 



Inflorescence fastigiate (the heads in close clusters); under surface of leaves con- 

 spicuously punctate 2. V. fasciculata. 



Under surface of leaves (except the midrib and principal veins which are pubescent) 

 pubescent with the one-celled, appressed hairs and with few to many multicellular 

 hairs, all over the lower surface; also the lower surface of the blades more or 

 less densely punctate 3. V. missurica. 



1. Vernonia altissima Nutt. Tall Ironweed. Map 1978. Probably 

 found in every county of the state although there are no authentic reports 

 from the northwestern counties. Usually frequent to common or abundant 

 in the eastern part of the lake area and in the Tipton Till Plain, becoming 

 rare in the unglaciated area. It has a wide range of habitat and is found in 

 dry, open or moist woodland, fallow fields and prairies, and rarely in dried- 

 up sloughs and swamps. 



Pepoon's reports for Hill and for Umbach from Porter County are re- 

 ferred by Fassett (Rhodora 35: 202. 1933) to V. missurica Raf. 



N. Y., Ohio, and Mo., southw. to S. C, Ga., and La. 



la. Vernonia altissima var. lilacina Clute. (Amer. Bot. 36: 225. 1930.) 

 This is a form with "pinkish-lavender" flowers which was found on the 

 campus of Butler University at Indianapolis. 



The flowers of this species are variable, ranging from purplish, the 

 normal color, to colorless (white). In the white form the bracts are usually 

 green with no trace of purple. I have seen this form several times. In a 

 pasture of about five acres in Montgomery County it was noted re- 

 peatedly. 1 have collected a rose colored form in Lagrange County. I have 

 had the white and rose colored forms in cultivation for several years and 

 as far as I have been able to determine, they continue the same color forms. 



