IRONWEED
ironweed, vernonia
(noun) any of various plants of the genus Vernonia of tropical and warm regions of especially North America that take their name from their loose heads of purple to rose flowers that quickly take on a rusty hue
Source: WordNet® 3.1
Etymology
Noun
ironweed (countable and uncountable, plural ironweeds)
Any of certain species of the genus Vernonia of forbs and shrubs.
Source: Wiktionary
I"ron*weed`, n. (Bot.)
Definition: A tall weed with purplish flowers (Vernonia Noveboracensis).
The name is also applied to other plants of the same genus.
Source: Webster’s Unabridged Dictionary 1913 Edition