Corn cleavers  (Galium tricornutum)

Classified as Critically Endangered in Great Britain (3). Corn cleavers is a UK Biodiversity Action Plan (UK BAP) priority species, for which Plantlife is lead partner (4).

Corn cleavers is an endangered plant that has bristly stems and produces thin leaves in whorls of up to nine. The double fruits are hairless and supported on stalks that curve downwards (2). These seeds were once used as pin-head covers by lace-makers to protect their fingers (5).

This plant was once common in southern, central and eastern England but has suffered a severe decline. It now occurs in just three sites; one in Rothamsted, one near Oxford and a third in Cambridgeshire (6). In southern Europe the species is relatively common, although it is probably declining (4); it is very rare in north Europe (3).

You can view distribution information for this species at the National Biodiversity Network Gateway.

Inhabits disturbed ground (3) in arable land, waste ground, coastal cliffs, and hedgerow banks (6).

This annual plant typically germinates in autumn and flowers between May and September (3). It seems unable to co-exist with competitive plants and so is therefore associated with open areas where there is sparse vegetation, such as the very edge of fields (3).

Agricultural intensification is largely responsible for the precipitous decline of this once common species (6), starting towards the end of the nineteenth century when seed cleaning techniques were improved (3). More recent threats include the use of herbicides and fertilisers, the loss of field-margins, the use of more productive crops and alterations in the traditional style of crop rotation (6).

This plant is a UK Biodiversity Action Plan priority species; Plantlife, the wild plant conservation charity, is the lead partner responsible for coordinating the implementation of the Species Action Plan devised to guide the conservation of corn cleavers. The plan aims to encourage the colonisation of new sites, and reintroduce corn cleavers to eight former sites by 2003 (6).

The UK Biodiversity Action Plan for this species is available at UK BAP.

There may be further information about this species available via the National Biodiversity Network Gateway.

For more on this species see:

Plantlife Species Dossier:
http://www.plantlife.org.uk/uk/assets/saving-species/saving-species-dossier/Galium_tricornutum_dossier.pdf