\Per"i*gone\, n. [Pref. peri- + Gr. ? productive
organs.]
1. (Bot.)
   (a) Any organ inclosing the essential organs of a flower;
       a perianth.
   (b) In mosses, the involucral bracts of a male flower.
2. (Zo["o]l.) A sac which surrounds the generative bodies in
   the gonophore of a hydroid.