Sweet chestnut

Castanea sativa attains a height of 20–35 m with a trunk often 2 m in diameter. The bark often has a net-shaped pattern with deep furrows or fissures running spirally in both directions up the trunk. The oblong-lanceolate, boldly toothed leaves are 16–28 cm long and 5–9 cm broad.
The flowers of both sexes are borne in 10–20 cm 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. The raw nuts, though edible, have a skin which is astringent and unpleasant to eat when still moist; after drying for a time the thin skin loses its astringency but is still better removed to reach the white fruit underneath. Cooking dry in an oven or fire normally helps remove this skin.