Nyctaginaceae, the four o'clock family, is a family of around 33 genera and 290 species of flowering plants, widely distributed in tropical and subtropical regions, with a few representatives in temperate regions. The family has a distinctive fruit type called an accessory fruit or anthocarp, and many genera have extremely large pollen grains.
Nyctaginaceae
Bougainvillea glabra
An accessory fruit is a fruit that contains tissue derived from plant parts other than the ovary. In other words, the flesh of the fruit develops not from the floral ovary, but from some adjacent tissue exterior to the carpel. As a general rule, the accessory fruit is a combination of several floral organs, including the ovary. In contrast, true fruit forms exclusively from the ovary of the flower.
A selection of accessory fruits (from left to right: pear, fig, and strawberry)
Apple section, showing seeds plus papery expression of the ovary, surrounded by tissue formed from ripening of the hypanthium
On this strawberry, the many pips located on the surface have germinated in a phenomenon known as vivipary. The pips of the strawberry are its true fruit.
The cashew ‘apple’ and its attached drupe, which contains the edible seed
