Don't worry, that's just the V-graft joint. Plumeria are often grafted onto root stock, just like fruit trees, to give the cutting an instant root system.

Thank you- I think I need to buy them a book to help them a long!

Yes its a grafted plant. Growers graft hybrid plants onto common plumeria stock to get then to the market faster. Growing from a cutting can take months and does not always work. However, a graft plant is ready in a few short weeks!

Adeniumrose Company rare
and unusual cactus, succulent plants, exotic plants and supplies.