When is red yellow?

I promised my class that by the end of the semester they'd know why flamingos are pink and Cheetos are orange. In that vein, last week's quiz included a question asking them to figure out which of two labels belonged on a bottle of reddish violet solution and which went on the yellowish solution.

One student correctly labled the bottles, but wondered if my choice of compounds was a red herring. She noted that the name of the compound that she predicted would produce the reddish solution (canthaxanthin) meant "yellow" in Greek. I told her that, in fact, I hadn't known that xanthin meant yellow and wasn't trying to mislead them!

This sent me on a hunt to discover why a reddish compound was named for "yellow". Turns out canthaxanthin is named for the mushroom species from which it was first extracted (Cantharellus cinnabarinus) and the Greek for yellow (xanthin). Cantharus is Latin for a two horned drinking cup, which the fungus resembles. The color can tend toward the orange, so that may be the source of the "yellow" in the name.