This species Begonia is native to northern Vietnam. Edgar Irmscher first published this name in 1921. Horticulturally, it is classified as thick-stemmed, trunk-like, non-ramified by the Thompsons. It blooms in the winter with white to light pinkish flowers.
There are less than 100 different species and hybrids in this unusual thick-stemmed grouping. They rarely make full, bushy, attractive hybrids that attract so many of us. They do provide an unusual-looking contrast for most plants in regular collections.
The thick-stems are characterized by having thick stems even as young plants. To be classified as trunk-like, non-ramified, a begonia must have stems that are stout and internodes that are short. This group does not branch readily along the stems, but does send up basal growth. Leaves are only at the top of each stem giving the plant a tree-like appearance.
Branch member Morris Mueller grew this specimen under lights. He suspects that this plant would suffer major leaf drop in cold that many other begonias just ignore. Under lights, it still tends to go dormant as winter approaches. Fall is when mildew starts appearing, but one treatment with a Bayleton product eliminates the problem until the next fall.
As this plant became pot bound it dried out quickly, so quickly that it would wilt before all other plants on the same shelf. Interestingly, this wilting between waterings seemed to do the plant no harm at all.
After a few years, this plant has bloomed for him for the first time. It bloomed in January and all the blooms were male. It is coming into bloom a second time this season and all the blooms again look like they are male.