Your unknown looks very much like an oldie 'Corallina de Lucerna', often called Lucerna or Angel Wing Begonia (but it seems like a lot of cane begonias are simply called angel wings). This is my oldest cane - about 42 years old now that I've kept going by cuttings over the decades.

Here is a very tall Lucerna at one of the ABS conventions which was grown in a year or two (in semi-tropical Miami).

And one of my own

Thank you. It does look like it. It's a stunning begonia.

This is Medora when I purchased it this spring. It's been an extremely good grower.

The above picture was taken March 26th and this one was taken today.

Good job! Looks like it is loving its new home.