Fruit
The ripened ovary of a flower, which holds and spreads the seeds.
To a botanist, any structure that grows from a flower's ovary and holds seed is a fruit. That includes apples and mangoes, and also dry things such as a poppy capsule, a pea pod, a maple key and a sunflower 'seed' in its shell. Some fruits are part of flower decoration in their own right: rose hips, lotus seed heads, poppy heads, physalis lanterns and berries on a branch are all used in arrangements, especially in autumn and winter.