aMonosepalous(Bot) 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. Cf. Monopetalous.
Century Dictionary and Cyclopedia
monosepalousIn botany, having the sepals united by their edges: more properly gamosepalous.
Chambers's Twentieth Century Dictionary
adjMonosepalousmon-ō-sep′a-lus (bot.) having the sepals all united: having a calyx of one piece.