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Alder buckthorn

Frangula alnus

Family · Rhamnaceae · Poisonous

ToxicTraditional use

Read this before the sheet

This plant, or one that resembles it, is dangerous. Identifying is not authorising: no app has the authority to tell you that you may eat or touch a plant.

Emergency
Alder buckthorn (Frangula alnus)Alder buckthorn (Frangula alnus)
Dmitry Makeev, CC BY-SA 4.0 · Dmitry Makeev, CC BY-SA 4.0

The streamside shrub whose berries go from green to red to black in the same cluster, and whose bark is one of the strongest purgatives in the European pharmacopoeia. The berries are toxic.

Where it grows

Streams and ditches · Oak woods · Uplands

Also known as

glossy buckthorn, black dogwood

In flower
In fruit

How to tell it

A thornless shrub or small tree, unlike common buckthorn. Alternate, oval, entire, glossy leaves with seven to nine pairs of very straight parallel veins, which is the best mark. Dark bark with pale lenticels. Green, red and black berries together on the same branch.

What it is confused with

Common buckthorn

Rhamnus cathartica

Confusion that poisons

Common buckthorn has thorns at the branch tips and leaves opposite or nearly so; alder buckthorn has no thorns at all and alternate leaves with strongly parallel veins. Both species' berries are strong purgatives and are not eaten.

What it is for

The bark, dried and aged at least a year, is an official laxative still in the pharmacopoeia. Fresh it is violently emetic and dangerous. The berries cause vomiting and severe cramps and are never eaten. Buckthorn charcoal was for centuries the best charcoal for black powder.

With documented traditional uses. Not a therapeutic indication and not a dose.

Where it occurs

Iberian Peninsula

Each square is an area with recorded observations of this plant. The lighter background is the set of areas where any of the entries has been observed, and serves as a reference. Note what this is not: it is not where the plant lives, it is where people record it, so trails and towns always look fuller than the mountains. Data from GBIF.

Sources

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