Box elder hollow form

My friend John Nicholson - a very skilled wood turner - makes a lot of these nifty hollow forms (vases), and is a great hands-on teacher. These photos show my version, turned in his shop while he kept at least half an eye on what I was doing (and told me what to do next!). This vase is turned from box elder and hasn't yet been finish sanded or had any finish applied - i.e., it's in the "raw" state. It stands almost 8" tall and is 5" across at the widest point. The most interesting thing about turning these - here's the magician describing the trick! - is that they are turned initially in one piece; then cut into two pieces, each of which is separately hollowed; then are glued back together; and then are finish-turned to final shape, detailed, etc. Can you tell which groove hides the glue joint? I used John's Derry Tools hollowing system to hollow the bottom part of the base. Let me know if you want to hear more about that.