You bought yourself a croton.

Billy Rae

Agreed. It's a croton. (Codiaeum variegatum)

Thank you for the fast replies! I read the blog that was linked, and I'll guess I have to wait and see how my new friend will fare at my house. He's in an east facing bay window and will get plenty of sun there over the winter, now that the leaves are falling off the trees outside. I'll just have to make sure to spray him with a spray bottle every so often for humidity. He's pretty snug in his pot right now, with roots coming out the top and the bottom. How big a pot do these crotons like, and what kind of soil?

Misting your plant won't raise the humidity, but merely wet the leaves for a few moments. Some people find that grouping large numbers of plants together helps raise the humidity in their environment. Others use small humidifiers or even little indoor fountains.

Try a humidity tray, that'll help a lot.

You can read up on them, &/or make one. I use a small saucer w/ small rocks & when I water, I water to overflow, which spills onto the rocks. The pot in turn sits ON TOP OF, not in, the water on the rocks. That helps the plant w/ some but not too much moisture.

I might not repot 'til spring unless it's really tight in the pot. This is a plant that can grow quite large if it's happy, like outside in the heat and humidity down here. I've seen them six or more feet high. They will really take off in the spring.