aaron's rod

Any of various plants with a tall flowering stem, especially:

Verbascum thapsus, the great mullein, common mullein, or hag-taper.

Goldenrod, the Solidago genus of North American plants with yellow flowers.

Hylotelephium telephium (syn. Sedum telephium; orpine, livelong, or live-forever).

(architecture) A rod-shaped molding decorated with an entwined snake, and sometimes leaves, vines, and/or scrolls.

(slang, dated, uncommon) The penis.

(archaic) A rod with one serpent twined around it, as used by Aaron (differing from the caduceus of Mercury, which has two serpents).