The glossy brown nuts of the Horse Chectnut tree, also known as conkers, are toxic to humans and many animals. They contain a substance known as a saponin which is called Aesculin. These substances destroy red blood cells. Some animlas, notably deer and squirrels are resistant to the toxin and the toxin can be wasjed out through mashing and frequent washes in boiling water. The trees, which flower in early summer and fruit in the Autumnare widely grown in temperate climates and the genus to which it belongs Aesculus was named by Linnaus after the Roman name for an edible acorn. The term "horse" is thought to be a reference to the strength of the nut rather and its usefulness as a food for horses is a myth. In North America the species is known as "Buckeye" also in reference to the nut, this time to its lustrous brown colour which is thought to be like that of a deer.