Source : Webster's Revised Unabridged Dictionary (1913)

Perula \Per"u*la\, n.; pl. {Perul[ae]}. [L., dim. of pera
   wallet, Gr. ?: cf. F. p['e]rule.]
   1. (Bot.) One of the scales of a leaf bud.

   2. (Bot.) A pouchlike portion of the perianth in certain
      orchides.