Cultivar: Baby Wing White
Bloom Color: White/Near White
Foliage: Herbaceous, Shiny/Glossy-Textured
This plant is attractive to bees, butterflies and/or birds. Suitable for growing in containers.
Photo: Atlanta Botanical Garden, Atlanta, Georgia, USA 
Source: Dave’s Garden
Begonia grandis [hardy begonia] is a plant in the begonia family, Begoniaceae. It is an herbaceous plant with alternate, simple leaves, on arching stems. The flowers are pink or white, borne in fall. As the common name “hardy begonia” implies, it is one of the hardiest species or cultivars of begonias.
Photo: Cloud Forest, Gardens by the Bay, Singapore 20120629
With around 1,500 species, Begonia is the sixth largest genera of flowering plants. The American Begonia Society classifies begonias into several major groups: cane-like, shrub-like, tuberous, rhizomatous, semperflorens (or wax begonias), rex, trailing-scandent, thick-stemmed.
Reiger Begonias are a hybrid cross between tuberous and wax Begonias. They are not known in truly wild environment. Reiger Begonias produce beautiful ‘rose-like’ blooms in bright yellows, reds, pinks, and even white.
The Rieger begonia is also known as hiemalis begonia. The original plant was a cross between a standard wax begonia and a tuberous begonia and has since evolved into a thriving category of its own. They are also sometimes called elatior begonias.
Today, the flower variety is achieved by crossing existing hybrids with each other and standardizing for color.
Photos: Flower Dome, GBTH, Singapore 20120629
Source: Wikipedia, House Plants: Reiger Begonias