The variation in chromosome number found within one and the same endosperm in species ofCoffeacan probably be ascribed to: 1) endoreduplication producing cells with euploid chromosome numbers, multiple of the initial ploidy level; 2) endoreduplication of only some of the chromosomes; 3) unequal anaphases. The mechanisms 2 and 3 would produce cells with aneuploid chromosomes numbers, at any ploidy level. Such phenomena occur either independently or concomitantly.