Commonly known as the “castor-bean begonia”, this is an artificial hybrid (Begonia barkeri x heracleifolia). It was published in 1847 by German botanist Albert G. Dietrich, making it one of the oldest known hybrid begonias.
It is a large rhizomatous plant with green, multi-lobed leaves up to 25cm across. The stems are covered in numerous reddish hairs. The white flowers seen on modern plants differ from the original description of “rose-red”. The reason for this is unknown.