Not actually a begonia, but you should treat it like one!
Pellionia pulchra thrives in humidity, making it a great choice for filling out space in greenhouse cabinets or a terrarium. This plant can also adapt to household conditions, but avoid drafts & disruptions from heaters. Growth pattern mimics that of begonia 'withlacoochee', happily creeping or spilling from its pot. Bright indirect to medium-low light. Water when potting mix is dry to the touch, allowing to dry only a little more in cooler months.