The Collaborative International Dictionary of English v.0.48:
leopard's bane \leop"ard's bane`\ (l[e^]p"[~e]rdz b[=a]n`) n. (Bot.) A name of several harmless plants, as Arnica montana (Arnica acaulis syn. Doronicum acaule), Senecio Doronicum, and Paris quadrifolia. Syn: leopardbane, leopard's-bane. [1913 Webster +PJC]The Collaborative International Dictionary of English v.0.48:
leopardbane \leop"ard*bane\ (l[e^]p"[~e]rd*b[=a]n`), n. Any of several herbs of the genus Doronicum (as Doronicum acaule syn. Arnica acaulis) having alternate often clasping stem leaves cultivated for their long stalks of yellow flower heads. See leopard's bane. Syn: leopard's-bane, leopard's bane. [WordNet 1.5 +PJC] false" leop`ard*bane (f[add]ls" l[e^]p`[~e]rd*b[=a]n`), n. Any of several herbs of the genus Doronicum, such as the great false leopardbane (Doronicum pardalianches) of North America and the oriental false leopardbane (Doronicum orientale syn. Doronicum caucasicum). [PJC]