Castanea sativa

Castanea sativa, the sweet chestnut, Spanish chestnut or just chestnut, is a species of tree in the family Fagaceae, native to Southern Europe and Asia Minor, and widely cultivated throughout the temperate world. A substantial, long-lived deciduous tree, it produces an edible seed, the chestnut, which has been used in cooking since ancient times.

The tree is to be distinguished from the horse chestnut Aesculus hippocastanum, to which it is only distantly related. The horse chestnut bears similar looking seeds (conkers) in a similar seed case, which are not palatable to humans. Other common names include "Spanish chestnut", or "marron" (French for "chestnut"). The Latin sativa means "cultivated by humans". Some selected varieties are smaller and more compact in growth yielding earlier in life with different ripening time: the Marigoule, the Marisol and the Maraval.

C. sativa attains a height of 20-35 m (66-115 ft) with a trunk often 2 m (7 ft) in diameter. The bark often has a net-shaped (retiform) pattern with deep furrows or fissures running spirally in both directions up the trunk. The trunk is mostly straight with branching starting at low heights. Sweet chestnut trees live to an age of 500 to 600 years. In cultivation they may even grow as old as 1000 years or more. Their large genetic diversity and different cultivars are exploited for uses such as flour, boiling, roasting, drying, sweets or wood. The oblong-lanceolate, boldly toothed leaves are 16-28 cm (6-11 in) long and 5-9 cm (2-4 in) broad.

The flowers of both sexes are borne in 10-20 cm (4-8 in) long, upright catkins, the male flowers in the upper part and female flowers in the lower part. In the northern hemisphere, they appear in late June to July, and by autumn, the female flowers develop into spiny cupules containing 3-7 brownish nuts that are shed during October. The female flowers eventually form a spiky sheath that deters predators from the seed.