acalysinous

from The Collaborative International Dictionary of English v.0.48

Acalycine \A*cal"y*cine\, Acalysinous \Ac`a*lys`i*nous\, a. [Gr.
   'a priv. + ? calyx.] (Bot.)
   Without a calyx, or outer floral envelope.
   [1913 Webster]