Tropical House Plant Sick?

Hi, I pulled out my Houseplant Identification book,and the closest I could find to what your describing is (there are three) Codiaeum,or croton a Hawaiian Ti, or Dracaena or Corn Salk plant. Really it doesn't make much difference to what it is because whatever it is, it has root -rot. If it feels mushy on the trunk, that's what it is, You can try to save it by getting it immediately out of the pot, and let the roots have a little air. I'd set it aside for about an hour,out of it's pot. Be careful when you brush the dirt away from the roots of the plant, allot of them will be mushy too. With sterilised scissors, snip away the mushy ones(roots that is) You'll want to get a new pot,or scrub the old one clean,but you really should get a new pot, an inch bigger than the old one.You should mix some Good potting soil, some garden sand, some perlite(about one third of the total mixture) and I like to add a little orchid mix (fine) to it because it adds ? well, I don't know what it adds, but I do it anyways. Mix it all together,then with some broken pieces of pottery,rocks in the bottom of the new pot, re-pot your plant. Afterwards,soak it with some Quick Start,to prevent trans plant shock. You could also dip the roots of the plant in some Rooting Compound first. That's all I can do to help you on the matter.Sorry I don't know more. Byee