follicle

A milkweed follicle releasing its seeds. In botany, a follicle is a dry unilocular fruit formed from one carpel, containing two or more seeds. It is usually defined as dehiscing by a suture in order to release seeds, for example in Consolida (some of the larkspurs), peony and milkweed (Asclepias).

Some difficult cases exist however, so that the term indehiscent follicle is sometimes used, for example with the genus Filipendula, which has indehiscent fruits that could be considered intermediate between a (dehiscent) follicle and an (indehiscent) achene.