Irvingia is a genus of African and Southeast Asian trees. I. gabonensis, also known as wild mango, African mango, or bush mango, is the species depicted below, which I photographed outside of Libreville, in Gabon.
Although unrelated to the mango (Mangifera indica), I. gabonensis has edible fruit that have the outward appearance of small mangos. They are especially prized for their edible, fat and protein-rich seeds/nuts. The nuts are extracted from the fruit and dried in the sun for preservation. They can be seen sold in markets whole or in powdered form. They are also ground into a paste known as dika bread or Gabon chocolate. The seeds are highly mucilaginous, and thus used as a thickening agent in soups. A vegetable oil can be extracted from the pressed nuts.
Here is a very informative PDF on the potential of Irvingia gabonensis for integration into smallholder agroforestry systems:
A photo of the fruit, below. Click to enlarge.
Below is a photo of the trunk of Irvingia gabonensis, covered in vines and epiphytes…