I found this plant on a balcony in October in Wisconsin about 9 years ago. It was simply a stick in some dirt. I brought it indoors and it started to grow. I have transplanted it once. I have never been able to figure out what kind of plant it is. It grows very long vines from a woody center stalk. If the vines are cut they bleed a milky white, sticky sap. I don't think that it is supposed to be as large as it is, but I have no idea how to prune it. I know that it prefers a southern or eastern exposure. Any help would be appreciated. As a side note: One time there was a huge bloom of chartreuse mushrooms in the soil around the plant. They lasted about 12 hours and then died. They didn't seem to affect the plant at all, but were interesting, nonetheless.
That's it exactly. Thanks for the quick response! It's been a mystery to me for so many years... Now, does anybody know the best way to prune it so the stalk grows higher while the "vines" grow fuller "not so thin"?