Webster's Revised Unabridged Dictionary · 1913

Monosepalous

Monosepalous , adjective

[Mono- + sepal: compare French monosépale.]

(Botany) Having only one sepal, or the calyx in one piece or composed of the sepals united into one piece; gamosepalous.

The most recent writers restrict this term to flowers having a solarity sepal, and use gamosepalous for a calyx formed by several sepals combined into one piece. Compare Monopetalous.