Oak

(Quercus robur L.=Common Oak, Quercus petraea (Mattuschka) Liebl. Sessile Oak, Fagaceae)

Also called: Tanners Bark.

Description: Trees up to 40m (130ft) high; the young bark is smooth, becoming fissured with age. In 0. robur the leafstalks are up to 1 cm (0.4in) long and the fruits are clustered on a long penduncle; in Q. petraea the leafstalks are 1 cm (0.4 in) or more long and the fruits are in groups of 2-3 on a very short peduncle.

Part Used: Mainly the dried smooth bark from young branches 5-10 years old, rarely also the dried leaves or the dried roasted fruits. The older fissured bark is much less active.

Habitat and Collection: Both species and numerous intermediate forms are found throughout Europe. The common oak is one of our stately British trees, it prefers clay soils; the sessile oak is found on silicious and acid soils. The bark should be collected from branches in May and is dried either in the shade or in sunlight with free circulation of air or artificially at 50-60'C (122 140"F).

Constituents and Action: The bark, leaves and fruits contain tannins. They are anti-inflammatory on mucosa and as astringents are used in chronic diarrhoea and dysentery.

Usage: Internally as a tisane or in powder form (a knife-pointful 4-5 times a day) for diarrhoea (little used). Externally a decoction (allow to boil for 10 minutes 50-100g (1 •75-3.5oz) of chopped bark in 1 litre (1 •75pt) of water) is used as a gargle or mouthwash for sore throats, as a vaginal douche for leucorrhoea and as an application for burns, chilblains and haemorrhoids.