[Rhizomatous] Begonia x 'Cathedral'
Native range: Human-made hybrid, not found in nature
Known names: --
Hardiness: Best kept above 60°F
Mature Size: ~10" Tall, ~12" Wide
Light: Low light, early morning sun only.
Water: Only water once the top 1" of the soil feels dry. Let water run through the pot. 
Soil: Fast draing, coarse indoor potting soil.
Dormancy Period: N/A
Pet-Safe: No
Plant Size: Grown in 4" pot, shipped semi bareroot. 
 
This Begonia is quite amazing! When viewed from the underside, parts of the leaves will allow light to pass through the thin membrane resembling stained glass windows that you would find in a cathedral (hence the name).