Source : Webster's Revised Unabridged Dictionary (1913)

Monochlamydeous \Mon`o*chla*myd"e*ous\, a. [Mono- + Gr. ?, ?,
   cloak: cf. F. monochlamyd['e].] (Bot.)
   Having a single floral envelope, that is, a calyx without a
   corolla, or, possibly, in rare cases, a corolla without a
   calyx.