cypsela

from The Collaborative International Dictionary of English v.0.48

Cypsela \Cyp"se*la\ (s?p"s?-l?), n. [NL., fr. Gr. kypse`lh any
   hollow vessel.] (Bot.)
   A one-seeded, one-celled, indehiscent fruit; an achene with
   the calyx tube adherent.
   [1913 Webster]