Marcos, Involucrata has to much genetic variation, what makes that a fruit from tree "A" can be totally different from the fruit of the tree "B". The shape can be rounded or oval, the color intense-red or dark-red, almost black. The size can vary from 2 to 4 cm, but the flavor is the worst... can be very sweet, acid, or just taste like water!!
I hope that you have at least one good cultivar between those trees.
Also, in my experience, I figured the flavor changes quickly after you harvest them.