Grains of Selim are the seeds of a shrubby tree, Xylopia aethiopica, found in Africa. The seeds have a musky flavor and are used as a spice in a manner similar to black pepper, and as a flavouring agent that defines café Touba, the dominant style of coffee in Senegal.
It is also known as Kani pepper, Senegal pepper, Ethiopian pepper, and (historically) Moor pepper and Negro pepper.
It also has many names in native languages of Africa, the most common of which is diarr in the Wolof language (this is the name used on most packages of café Touba).
It is called 'Etso' in the Ewe language of Ghana. It is sometimes referred to as African pepper or Guinea pepper, but these are ambiguous terms that may refer to Ashanti pepper and grains of paradise, among others.