Spiny cocklebur
Xanthium spinosum
Family · Asteraceae · Poisonous
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.
The plant with yellow trident spines at the base of every leaf, its fruits burs covered in hooks that catch on everything. It came from South America and is now everywhere in the Peninsula.
Roadsides and waste ground · Fields and pasture · Town and roadside · Streams and ditches
Also known asBathurst burr, spiny burweed
How to tell it
At the base of every leaf sits a strong yellow spine split into three points, which is the immediate mark. Narrow three-lobed leaves, dark green above and white-felted beneath. Oval fruits a centimetre long, covered in hooks, clustered along the stem.
What it is confused with
No dangerous lookalikes known in the Iberian Peninsula.
What it is for
None. The seedlings and seeds contain carboxyatractyloside, a potent liver toxin that kills pigs and cattle that eat them, and fatal human cases are described. The burs clinging to wool carried it round the whole world.
The law says
A listed invasive alien species in Portugal. Do not carry or propagate it, and it is worth pulling the burs off your clothes before moving to another valley.