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.
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Cupule: A fruit structure that protects the seed. It can be fully closed or releases the seed when it becomes mature by opening with 4 valves. Here is the dictionary definition: http://www.biology-online.org/dictionary/Cupule
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