A re-evaluation of the structure of the mango ovule in comparison with those of a few other Anacardiaceae species

The mango ovule has been described by some authors as unitegmic and by others as bitegmic, but in the latter case with integuments fusing quite early. The results of this investigation suggest that it is a pachychalazal ovule in that the greater part of the ovular envelope consists of chalazal tissue and that only the micropyle is formed by one massive integument. The pachychalazal ovule could possibly be a characteristic of the tribe Anacardieae. Bitegmic ovules in which the outer integument is continuous with two labellate outgrowths of the massive funicle (‘raphe-chalazal ovules’) are apparently characteristic of the tribes Spondieae and Rhoideae. All previously investigated species as well as Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro and Lannea discolor (Sond.) Engl. were found to be chalazogamous.