Answer: "Marble Queen" is the white variegated form of Pothos. They are just as easy to grow as the rest of the Pothos family. With it's white coloration "Marble Queen" will need a little brighter light to maintain it's color than "Jade" or "Golden Pothos" requires. If placed in to low of lighting the leaves with a lot of white variegation will slowly die off. The leaves with a small amount of white variegation will slowly turn green. Eventually your plant will turn into a solid green "Jade Pothos". Although you have it in a south-facing window, it simply isn't getting the bright light it craves. Try putting it in a west-facing window.
Hope this helps!
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