Nami's Mikan Trees

After the Arlong arc, three orange trees from Bellemere's grove were added to the top of the Going Merry. The fruits they bear are satsumas (Citrus unshui), but are usually translated as tangerine or oranges. Nami treats them with care, as they are mementos of Bellemere. They provide the crew with vitamin c as well as decor for the ship.

Aside from Nami taking care of them, Sanji also protects these three trees from those who might otherwise harm them or steal the fruit (e.g. Luffy).

After Luffy and Usopp's battle in Water 7, these trees were moved to the hotel room where the Straw Hats were. They were luckily found by the Galley-La shipwrights and moved to a safer location before the Aqua Laguna hit.

They, along with the rest of the Straw Hats' belongings, now reside on the Thousand Sunny.