WordNet (r) 3.0 (2006):

woolly mullein
    n 1: tall-stalked very woolly mullein with densely packed yellow
         flowers; ancient Greeks and Romans dipped the stalks in
         tallow for funeral torches [syn: common mullein, great
         mullein, Aaron's rod, flannel mullein, woolly
         mullein, torch, Verbascum thapsus]