For the indecisive fruit-eater, a pluot presents an obvious solution. When one cannot decide between the pulpy purpleness of a plum or the orange orb of an apricot, one can always reach for the pluot, a trademarked hybrid of the two fruits developed in the 1980s by lifelong stone-fruit breeder Floyd Zaiger.

But the math behind the pluot complicates this too-easy answer to fruit indecision. The golf-ball sized red inventions are not simply half apricot and half plum. When Zaiger performed his plant magic, he bred, not a plum and an apricot, but an apricot and a plumcot—itself a crossbreed of an apricot and a plum performed by Luther Burbank. Thus the parentage of the pluot could not be delineated as a simple 50/50 split, but with a ratio of 3/5 plum and 2/5 apricot.

But that was in the 1980s, a time of simpler fractions. Today, due to frequent crossbreeds and back crosses in the hunt for improved flavor and adaptability, the ratios are impossible to pinpoint. Leith Gardner, daughter of Floyd Zaiger and a fruit engineer herself, puts the lineage at 9/16 plum and 7/16 apricot, though even that’s not right because “now we’re even putting some peach into them.”

That’s not to be confused with the peacotum, another Zaiger creation that meshes some ratio of peach, apricot and plum. Or the Dapple Dandy or Dinosaur Egg, varieties of plum and apricot hybrids that may or may not be pluots or plumcots, depending on which Internet source you check. And all of these are distinct from the aprium, which began as a pluot reverse (3/5 apricot and 2/5 plum) but whose ratios have also been obscured by hybridization.

Zaiger, 85, continues to confound and delight fruit-eaters with his creations. Gardner says he’s excited about a new hybrid of peaches, plums, and cherries, which he’s calling a “peapluerry.” (Spelling, and mathematical ratios, unknown.)

For those who would rather deal in decimals rather than fractions, pluots are selling for $2.98 a pound at Calomiri’s at Eastern Market.