Maltese star thistle

Centaurea melitensis

Family · Asteraceae · Irritating

The yellow knapweed of dry fields and fallow land, with small heads armed with straight spines in a star. It covers abandoned ground all over the south at the end of spring.

Where it grows

Fields and pasture · Roadsides and waste ground · Town and roadside · Scrubland

Also known as

Maltese centaury, tocalote

In flower

How to tell it

An upright plant with a stem winged by continuous green wings running down from the leaves. Small heads, a centimetre across, with yellow florets. The bracts end in a central spine five to ten millimetres, with two or three pairs of smaller spines at its base, forming a star.

What it is confused with

Purple star thistle

Centaurea calcitrapa

Harmless confusion

Colour decides: yellow on Maltese star thistle, purple on the star thistle. And the star thistle has far larger spines, two to three centimetres, and a wingless stem.

Open sheet →

What it is for

No use. It is an aggressive invader in California and Australia, where it travelled in cereal seed, and is a clear indicator of degraded pasture.

Sources

Flora-On