Alder, Common

Botanical: Alnus Glutinosa (GAERTN.)
Family: N.O. Betulaceae

---Synonym---Betula Alnus.
---Parts Used---The bark and the leaves.
---Habitat---Europe south of the Arctic Circle, including Britain, Western Asia, North Africa.

---History---The English Alder is a moderately-sized tree or large shrub of dark colour, usually growing in moist woods or pastures or by streams. The leaves are broadly ovate, stalked, and usually smooth. The catkins are formed in the autumn, the fruiting ones having scales rather like a tiny-fir-cone; the flowers appear in early spring, before the leaves are fully out. The woody, nearly globular female catkins are the so-called 'berries.' The trees are often grown in coppices, which afford winter shade for stock on mountain grazings without appearing to injure the grass beneath, and can be cut down for poles every nine or ten years.

The wood is much used. When young it is brittle and very easily worked. When more mature it is tinted and veined; in the Highlands of Scotland it is used for making handsome chairs, and is known as Scottish mahogany. It has the quality of long endurance under water, and so is valuable for pumps, troughs, sluices, and particularly for piles, for which purpose it is said to have been used in sixteenth-century Venice and widely in France and Holland. The roots and knots furnish good material for cabinet-makers, and for the clogs of Lancashire mill-towns and the south of Scotland the demand exceeds the supply, and birch has to be used instead. It is also used for cart and spinning wheels, bowls, spoons, wooden heels, herring-barrel staves, etc. On the Continent it is largely used for cigar-boxes, for which its reddish, cedar-like wood is well adapted. After lying in bogs the wood has the colour but not the hardness of ebony. The branches make good charcoal, which is valuable for making gunpowder.

The bark is used by dyers, tanners, leather dressers, and for fishermen's nets.

---Dyeing---The bark is used as a foundation for blacks, with the addition of copperas. Alone, it dyes woollens a reddish colour (Aldine Red). The Laplanders chew it, and dye leathern garments with their saliva. An ounce dried and powdered, boiled in three-quarters of a pint of water with an equal amount of logwood, with solution of copper, tin, and bismuth, 6 grains of each, and 2 drops of iron vitriol, will dye a deep boue de Paris.

Both bark and young shoots dye yellow, and with a little copper as a yellowish-grey, useful in the half-tints and shadows of flesh in tapestry. The shoots cut in March will dye cinnamon, and if dried and powdered a tawny shade. The fresh wood yields a pinkish-fawn dye, and the catkins a green.

The leaves have been used in tanning leather. They are clammy, and if spread in a room are said to catch fleas on their glutinous surface.

---Constituents---The bark and young shoots contain from 16 to 20 per cent of tannic acid, but so much colouring matter that they are not very useful for tanning. This tannin differs from that of galls and oak-bark, and does not yield glucose when acted upon by sulphuric acid, which, it is stated, resolves it into almine red and sugar.

---Medicinal Action and Uses---Tonic and astringent. A decoction of the bark is useful to bathe swellings and inflammations, especially of the throat, and has been known to cure ague.

Peasants on the Alps are reported to be frequently cured of rheumatism by being covered with bags full of the heated leaves.

Horses, cows, sheep and goats are said to eat it, but swine refuse it. Some state that it is bad for horses, as it turns their tongues black.