The Ironweeds Table 1 - The P&PDL Picture of the Week - Plant & Pest Diagnostic Laboratory, Purdue University

Table 1. A comparison of three Indiana ironweeds².
Name	Height (ft)	Leaf width (in)	Leaf length (in)	Pubescence	Flowers
Tall ironweed (Vernonia gigantea)	5 to 10	0.5 to 1.5	4 to 12	May have sparse hairs on the stem. Leaves can have fine short hairs on the underside of the leaf.	May have sparse hairs on the stem. Leaves can have fine short hairs on the underside of the leaf.
Prairie ironweed (Vernonia fasciculata)	2 to 6	0.17 to 0.3	3 to 6	The leaves are almost hairless but may have some hair on both upper and lower surface.	Sept. 0.17 to 0.25 inches wide, 20-30 flowered.
Missouri ironweed (Vernonia missurica)	3 to 5	0.5 to 1.5	3 to 6	Stem covered with soft dense hairs. Leaf underside densely hairy on the underside of the leaves.	0.17 to 0.5 inches wide, 30 to 60 flowered.