Annual knawel Scleranthus annuus

Status Red - Endangered & Critically Endangered
Best Time to See June, July, August
Colour Green
Habitat Grassland, Arable, Farmland

A small rather easily overlooked plant with inconspicuous tiny green flowers.

Flowers lack petals and comprise five green pointed sepals that usually spread outwards when in fruit. Stems are erect or sprawling - up to 20 cm in length. The leaves are linear, pointed and in opposite pairs fused at the base.


It is native to Britain and widespread throughout, although absent from the very north and Outer Hebrides. In Ireland it is rare but scattered throughout.


A species of two distinct habitats – arable land, typically found in the margins of fields sown with winter cereals and also dry heathy grassland, the species more natural habitat.

Best time to see

Flowers from June to August


It is classified as ‘Endangered’ and is therefore considered to be facing a very high risk of extinction in the wild. It has declined significantly in Britain throughout its range with most losses since the 1950s. Listed as a Priority Species under the UK Biodiversity Action Plan.

Key threats

Within the arable habitat the main causes of decline are a direct result of the intensification of arable farming, the main reason being the introduction of broad-spectrum herbicides.