The family Annonaceous is regarded as being one of the most primitive of the Dicotyledons, since the fruits are in aggregates, that is , they are composed of several pistils which are fused with the receptacle, the whole being embedded in a white edible pulp.
The fruit Sour sop is the largest of all the species of Annona and may weight about 2 – 5 kg. The outer skin has many spines which are inclined towards the apex of the fruit. The flesh of the fruit is somewhat stringy but the flavor is slightly acid and very pleasant,. It is made into a refreshing drink and sometimes ice cream. Many wild forms exist in theCaribbean.
The sweet sop is sometimes called the sugar apple and is distinguished by the much roughened appearance of the outer skin, the carpels being incompletely fused. As with Sour sop (Graviola or Guanabana) the fruits of the sweet sop contain many seeds and it has an attractive flavor. The custard apple is perhaps the least popular of the fruits of this family. The skin is fairly smooth and it is difficult to detect that the fruit is composed of several fused carpels. The texture of the fruits is somewhat mealy.