noun, plural: cupulas
(botany) The cupule, together with the calybium, makes up the accessory fruit of some flowering plants (e.g. Fagaceae). In some genera, the cupule may even develop sharp spines, such as in Castanea. This type of cupule renders protection from seed predators.
Word origin: Late Latin cūpula, little cask, diminutive of Latin cūpa, tub.