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Allium sphaerocephalon (round-headed leek)

A threatened species in the UK, the round-headed leek belongs to the same genus as the familiar culinary plants onions, leeks, garlic and chives.
Allium sphaerocephalon

Allium sphaerocephalon (Photo: Patrice, licensed under CC by 3.0).

Species information

Common name: 

round-headed leek

Conservation status: 

Vulnerable D2 in the UK.


In scrubland, on dry rocky or stony hillsides or on beaches. A weed in cultivated localities, on roadsides and waste land.

Key Uses: 

Food, ornamental.

Known hazards: 

Allium species can cause digestive problems in humans if eaten in large quantities, and raw onion is poisonous to cats and dogs.


Genus: Allium

About this species

The familiar culinary plants onions, leeks, garlic and chives are all members of the genus Allium, which comprises approximately 750 species. You can recognise Allium species by the characteristic onion or garlic smell they emit when cut or otherwise damaged.

Round-headed leek can become a weed, spreading vegetatively via its bulblets or by bulbils in those forms that possess them.

Four subspecies of Allium sphaerocephalon are recognised. Most individuals belong to subspecies sphaerocephalon. White-flowered plants from Mediterranean islands and the Balkans with smooth flowers belong to subsp. arvense, while those from Greece and south-west Turkey with papillose flowers (with a roughened surface) belong to subsp. trachypus. Allium sphaerocephalon subsp. laxiflora is restricted to Sicily. Bulbil-bearing forms belong to subsp. sphaerocephalon, and are sometimes referred to as var. bulbilliferum.


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