hypanthium

from WordNet (r) 3.0 (2006)

hypanthium
    n 1: the cuplike or ringlike or tubular structure of a flower
         which bears the sepals and stamens and calyx (as in
         Rosaceae) [syn: {hypanthium}, {floral cup}, {calyx tube}]

from The Collaborative International Dictionary of English v.0.48

Hypanthium \Hy*pan"thi*um\, n.; pl. L. {Hypanthia}, E.
   {Hypanthiums}. [NL., fr. Gr. "ypo beneath + 'a`nqos flower.]
   (Bot.)
   A fruit consisting in large part of a receptacle, enlarged
   below the calyx, as in the {Calycanthus}, the rose hip, and
   the pear.
   [1913 Webster]