Taste the Rainbow

And I'm not talking about skittles (that would be breaking Lent). I'm talking about plants.

After eating some of my peppers and then sticking my tongue out at a particularly sassy mirror in my room, I made the discovery that bell peppers, not unlike lollipops, dye your tongue--granted, it is the back of your tongue, and it's not nearly neon enough, but it's there. Despite my (somewhat misleading title), I can't actually taste the rainbow (only a sunset, because I have only red, orange, and yellow peppers), but now I'm curious: What Lent-safe things can I use to dye my tongue? I get that this is a somewhat immature experiment, but I believe that an objective analysis will make me seem more like the college student that I am and less like the 4 year olds I babysit. These are the things I know:

--Watermelon does not dye your tongue. I presume that this is because there is so much water in it--so melons and other water-heavy things do not result in colorful taste buds.
--Grapes do not dye your tongue--given that grapes are not water-heavy (despite the awful bursting sensation when you eat them), I can only presume that this is because grape interior is not the same color as grape-exterior. Therefore, your tongue gets all confused, not knowing what part of the fruit to listen to. Same with apples, which also don't dye your tongue, but do make your teeth feel squeaky.

So:
In order to make your tongue colorful, the plant must be the same color throughout, and not incredibly watery. I think an observational study on the tongues of people who eat bananas and strawberries is in order...

I ate really well today (almonds and peppers and celery and what is still my favorite cereal), and am really looking forward to dinner tonight with my superwoman mom. I will eat rabbit food.