A big thank you to Douglas Justice for writing today's entry! – Daniel
The similarity of Xanthoceras sorbifolia and Aesculus hippocastanum is not evident until their husky capsules begin to split open. There is an obvious resemblance, but the genera are classified in separate subfamilies of Sapindaceae. Aesculus – the classical name for a kind of oak with edible acorns – was the name given by Linnaeus to the horse chestnuts and buckeyes. His reasons for applying this name to a genus that is so un-oak-like and whose fruits are poisonous, are evidently lost. Not so Xanthoceras, which means “yellow horn,” in reference to the small yellow projections on flowers of this species. See the previous BPotD entry on Xanthoceras here.
The glossy seeds of the horse chestnut are rich in toxic saponins. The seed and its extracts have been used for medicating horses suffering from gas, children's games (“conkers”), production textile whiteners and military armaments (see this excellent wikipedia entry). According to Ken Fern (Plants for a Future), “saponins can be easily obtained by chopping the seed into small pieces and infusing them in hot water. This water can then be used for washing the body, clothes etc. Its main drawback is a lingering odour of horse chestnuts.” The seeds of Xanthoceras are reported to be quite edible.