The Collaborative International Dictionary
Verticillaster
Verticillaster \Ver`ti*cil*las"ter\, a. [NL., fr. L. verticillus a whirl + aster a star.] (Bot.) A whorl of flowers apparently of one cluster, but composed of two opposite axillary cymes, as in mint. See Illust. of Whorl.
Wiktionary
verticillaster
n. (context botany English) A whorl of flowers apparently of one cluster, but composed of two opposite axillary cymes, as in mint.