Webster’s Revised Unabridged Dictionary · 1913
Perula
Per′u·la (pĕr′ū·lȧ), n.; pl. Perulæ (#). [L., dim. of pera wallet, Gr. πήρα: cf. F. pérule.] 1. (Bot.) One of the scales of a leaf bud.
2. (Bot.) A pouchlike portion of the perianth in certain orchides.