I found this pic on my phone the other day. I was having a Cara Cara Navel orange for lunch.
The typical Cara Cara has reddish-pink flesh, and is more tart than a standard navel. Here it looks like some of the segments got fertilized by some standard navel pollen. Is that how it works with citrus?
That's how corn works -- each kernel is pollinated individually -- so if you have different varieties planted too close to each other, they cross up but you get all different colors. Here's a pic of some corn in Belize from my diss work. This was all planted as white corn, but the farmer's son had planted a small patch of "black" corn about 50 yards away. He had it picked up in the north just to see what it would do. Their black corn is similar to what folks in the US call blue corn.
Really beautiful, but since my friends save the seed to plant the next crop, they tend to separate the white corn out for that purpose.
Also, most folks won't buy any corn but white corn, so they won't be able to sell the red/blue/black corn in the village if there's an opportunity to do so.