Skin (exocarp)The outer layer of the fruit wall. On a peach it is fuzzy.
Flesh (mesocarp)The middle layer of the fruit wall. It is the part you eat.
Pit (endocarp)The hard inner layer of the fruit wall. Also called the stone.
SeedIt lies inside the pit and can grow into a new tree.
A tomato 4
Pericarp (fruit wall)The wall of the fruit. It grows from the flower's ovary wall.
Septum (partition wall)A wall between two chambers. It is part of the pericarp.
Locule (seed chamber)A chamber inside the fruit. In a tomato it holds gel and seeds.
PlacentaFleshy tissue that carries the seeds. It grows from the inner angle of the chamber.
How this list was compiled: Every name was checked on 2026-09-30 against sources read that day; a name is kept only when two of them use it. (1) Wikipedia, text only: Drupe, https://en.wikipedia.org/wiki/Drupe (a drupe, or stone fruit: an outer fleshy part, the exocarp, or skin, and the mesocarp, or flesh, lies round one shell, the pit or stone, of hardened endocarp with a seed inside), Fruit (plant structure), https://en.wikipedia.org/wiki/Fruit_(plant_structure) (in fleshy fruits the pericarp is typically three layers, outer, middle and inner; the peach as the example of a drupe; in berries the entire pericarp is fleshy), Tomato, https://en.wikipedia.org/wiki/Tomato (the fruit develops from the ovary, its flesh comprising the pericarp walls; it contains locules, hollow spaces full of seeds; small varieties have two locules and globe-shaped ones three to five), and Locule, https://en.wikipedia.org/wiki/Locule . (2) Library of Congress, Everyday Mysteries, Is a coconut a fruit, nut or seed?, https://www.loc.gov/everyday-mysteries/agriculture/item/is-a-coconut-a-fruit-nut-or-seed/ , read in the Internet Archive copy (all drupes have three layers: the exocarp, the outer layer; the mesocarp, the fleshy middle layer; and the endocarp, the hard, woody layer that surrounds the seed; a drupe has a hard stony covering enclosing the seed, like a peach). (3) Colorado State University Extension, Colorado Master Gardener GardenNotes 136, Plant Structures: Fruit, https://cmg.extension.colostate.edu/Gardennotes/136.pdf (the ovary wall, or pericarp; the skin, flesh and pit of a peach are all derived from the pericarp; drupe: a fleshy fruit with a single seed, the pit; berry: a pulpy fruit with many seeds, as the tomato). (4) Thomas L. Rost, Tomato Fruit Anatomy, Section of Plant Biology, University of California, Davis, 1996, http://www-plb.ucdavis.edu/labs/rost/Tomato/Reproductive/anat.html , read in the Internet Archive copy (the tomato is a berry that develops from the ovary; the locules are surrounded by the pericarp; the pericarp includes the outer wall, the radial walls, or septa, and the inner wall, or columella; the pericarp and the placenta make up the fleshy tissue; the seeds lie inside the locular cavities). (5) John N. Martin, Botany for Agricultural Students, 1919, public domain, https://archive.org/details/botanyforagricul00mart (Figure 75, cross section of a tomato: ovary wall, placentas, seeds, partition walls, locules; the placentas are fleshy enlargements that grow from the inner angle of the locules and bear the seeds; Figure 76, lengthwise section through a plum: seed, wall of pit, fleshy portion). Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain curves; own work, nothing traced. Licence: own work
How it works
Parts of a fruit, shown on two fruits cut open. In the peach the fruit wall, called the pericarp, has three layers: skin, flesh and pit. In the tomato the wall is fleshy all the way through.
Read the full guide
The three layers of the pericarp
A fruit grows from the ovary of a flower, and the ovary wall becomes the pericarp. On a peach its three layers are easy to tell apart: the exocarp is the skin, the mesocarp is the flesh, and the endocarp is the hard pit. The seed lies inside the pit.
Inside a tomato
A tomato is a berry. Partition walls, the septa, divide the inside into chambers called locules. Each locule holds seeds in a gel, and the seeds are carried on a fleshy placenta.
The pit is not the seed. Crack a pit open and the seed is inside.
Small tomatoes often have two locules. Round ones usually have three to five.
Questions and answers
What are the three layers of the pericarp?
From the outside in: the exocarp, the mesocarp and the endocarp. On a peach they are the skin, the flesh and the pit. In a berry such as a tomato the whole wall is fleshy.
Is the pit of a peach the seed?
No. The pit is the endocarp, the hard inner layer of the fruit wall. The seed is inside it.
Is a tomato a fruit?
Yes. A fruit is what grows from the ovary of a flower and holds the seeds. A tomato does that, so to a botanist it is a fruit, and a berry.
What is a locule?
A chamber inside a fruit that holds the seeds. Cut a tomato across and the locules are the spaces full of gel and seeds between the partition walls.