Hi Andrew. Just seeing this post. Did you ever find one of these? I don't have it myself but did see it on the Logee's site.

Try this one more time. I've typed out two messages so far and lost both - GRRR! Okay, that is a rex but still rhizomatous. Rexes can be a bit more challenging but only in winter since they may/will go semi-dormant. I don't think that is what is happening here though. A new plant will take time to adjust to its new living quarters so it may pout for a while but two months should be plenty of time to settle in. Did you repot recently? It looks like the plant is too deep in the soil - the rhizomes should be exposed. You can remove the older leaves and restart those. Check other posts for propagating by leaf. It can be a challenge for the first few times until you get the hang of it. Rexes (and rhizomatous) can take more light but can also do okay in dimmer situations too. More light - healthier plant but more water. Less light - leaves may get bigger but won't be vibrant - requires less water. Let the plant help you decide on where it is most happy. A terrarium is another way of insuring a easier plant to take care of but it has its own set of issues as well. Are you saying you have high humidity in your home too? Usually outdoors is a wonderful growing area for the warmer months if you want to go that route. Just make sure you do provide some shady area to begin with. Here is an example of a rex I started by leaf pushing the top off this seed starting tray.

Kelly, I can mail you my begonia Sophie Cecile. It's 25 cm tall rooted plant. But postage is VERY expensive. If you're still interested, we'll discuss it by email.

Silvia, your begonias all look lush and full and happy. Are they porch plants? How often do you water them? Do you have any problem with slugs or snails? That was one of my big problems when I was in my begonia phase... and I just didn't use slug/snail bait often enough. Also, I'm realizing that your first photo in this thread, Silvia, looks the same or close to the plant in my first photo. That one is my favorite! I love the lime-green leaves. Hmm... I wonder what is the name? Russ, thank you for the I.D.! That looks like a match to me, too. I had many, many cane begonias at one time... then lost interest, and the slugs and snails did not. I moved on to obsession with other plants (bromeliads!). I still love begonias and I'm circling back to them with the acquisition of these new ones. You are exactly right... I knew that tuberous types don't survive in Florida and I incorrectly applied the same thinking to the rhizomes. I have these in clay pots and in all-day shade. Have not watered but God has watered a lot. Will they be ok, or do I need to move them out of the rain? Thanks! Carol