In the last of this little begonia quartet we have ‘Pollux’ – yes ‘Pollux’ – named after the closest giant star to the sun and one of the two stars in the Gemini constellation. This hybrid was, I guess, named for the constellation of silver spots on the leaves. It is a complex hybrid that is obviously related to the Rex begonias but the leaves are divided into leaflets and they are green, overlaid with silver, with red petioles (leaf stalks).
It is the smallest of the four I have mentioned this week and another that likes humidity and shade. It is a newbie, only introduced in 1994 and was raised in Japan (by Hideki Yamaguchi of plant breeding company Suntory). It is a hybrid of the Chinese B. circumlobata (with palmate leaves) crossed with Rex hybrid ‘The Chief’ which was then crossed with the Chinese B. hemsleyana which is from Yunnan and has palmate leaves with small silver spots. B. hemsleyana is one of those strange species that is challenging our opinion of begonias and is surprisingly hardy in the right spot and acts like a herbaceous perennial, dying down in winter and popping up again in (late) spring.
It is not the most flamboyant of begonias but very different from the others so I hope I can keep it happy.