kastanjen

Kastanjen is the Swedish term for trees that bear chestnut fruits and is used for two distinct groups within the plant family Fagaceae: the true chestnuts in Castanea and the horse chestnuts in Aesculus. The most familiar species are Castanea sativa, the sweet chestnut, whose edible nuts are widely consumed, and Aesculus hippocastanum, the horse chestnut, whose spiny fruit contains seeds that are not edible and can be toxic if eaten raw.

True chestnut trees are deciduous and can reach considerable size. Castanea leaves are long and simple with serrated margins, while horse chestnut leaves are palmately compound. The trees bloom in spring, with Castanea producing small pale catkins and Aesculus forming large showy panicles of flowers. After flowering, Castanea forms burrs that enclose edible nuts; Aesculus produces spiky capsules containing seeds commonly known as conkers.

Castanea sativa is native to southern Europe and western Asia but is cultivated widely in temperate regions for nut production. Aesculus hippocastanum is native to the Balkan region but is planted extensively as an ornamental and shade tree in cities around the world. Uses of the edible nuts include roasting, boiling, and incorporation into baked goods or flour; horse chestnut seeds are not consumed and can be toxic, though they have historic uses in traditional medicine and in decorative applications in parks and trails.

Culturally, chestnuts appear in autumn and winter markets and in various culinary traditions across Europe, where roasted chestnuts are a common seasonal treat.