Carline Thistle
Carlina vulgaris
Tap image to enlarge · Wikimedia Commons
Overview
The Carline Thistle is a strange and beautiful plant — a spiny thistle with a flower head that opens flat in sunshine, revealing golden-straw inner bracts surrounding the tiny central flowers. In winter the dried seedheads persist, looking like a flat compass rose. It grows on the shortest, most grazed calcareous dune turf. A good indicator species of old, undisturbed dune grassland. The flowers close in damp weather, which was historically used as a natural barometer.
At a Glance
| Order | Asterales |
| Family | Asteraceae |
| Habitat | Short calcareous dune grassland · Chalk and limestone grassland |
| UK population | Locally common on calcareous grassland and coastal dunes in England |
| Sefton Coast | Present in short calcareous dune grassland at Ainsdale; less common than on chalk downland |
| Conservation | UK Green List |
Where to See It
Short, dry calcareous dune grassland at Ainsdale NNR.
Identification
Stemless or short-stemmed thistle. Spiny leaves radiating from a rosette. Large flower head with golden-straw bracts opening flat in sunshine to reveal central flowers. Whole head closes in damp weather. Distinctive straw-gold colour.
Viewing & Photography Tips
Look in the shortest, most open dune turf at Ainsdale in August. The flat, star-like flower heads are distinctive. Also look for the dried stems of previous years' plants in winter.
Conservation Status
UK Green List
This species has a favourable conservation status in the UK and remains an important part of Sefton Coast biodiversity.
Frequently Asked Questions
Why does the Carline Thistle open and close its flower head?
The inner bracts of the Carline Thistle act as a hygrometer — they open in dry weather (facilitating pollination by insects) and close tightly in damp conditions (protecting the flowers from rain). This responsive behaviour is so reliable that the plant has historically been used as a natural weather indicator, hung in houses and used like a hygrometer. The movement is entirely passive — driven by water absorption and loss from the bract tissue.
Related Species
Plan your visit to the Sefton Coast
Marshside RSPB, Formby pinewoods, Ainsdale NNR — practical guides to getting there, what to bring, and the best spots for each season.