Broad-fruited corn salad  (Valerianella rimosa)

Classified as Critically Endangered in Great Britain (3).

The Latin name Valerianella means 'little valerian', and refers to the fact that this genus is affiliated with the valerians (4). Broad-fruited corn salad is similar in appearance to the more common species lamb's lettuce (Valerianella locusta). It is an erect plant with fairly brittle, highly divided stems, and produces small flowers that are arranged in clusters (5).

It is currently thought that broad-fruited corn salad occurs in less than 20 UK sites, in Somerset, Gloucestershire, Hants and probably elsewhere (6). It suffered a severe and sustained decline during the last 50 years (7). It was formerly known from much of England, Wales and Ireland and reached as far north as central Scotland (7). Elsewhere the species occurs in southern-central Europe, and is threatened in Germany, the Netherlands and Switzerland (3).

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

Inhabits arable fields and prefers calcareous soils (7).

Broad-fruited corn-salad is an annual plant that flowers from the end of June to late July and occasionally into August (7). Seeds are generally produced in August, and germination occurs towards the end of autumn (7). There are indications that the seeds may be able to remain dormant in the soil, as the species has reappeared after a number of years of absence at a site in Gloucestershire (3).

Many species occurring in arable fields and associated habitats have experienced a severe decline due to the changes in agriculture that took place following the Second World War. Main threats to this species include the use of chemical herbicides and fertilisers, the loss of field margin refuges, the decline of traditional systems of crop rotation, earlier harvests and the introduction of extremely competitive crop plants (7).

Broad-fruited corn salad is a priority species under the UK Biodiversity Action Plan, and Plantlife is the lead partner (6). This plan aims to maintain the current populations in the UK, and to help the species to return to at least eight former sites before 2003. One of the existing sites is a Site of Special Scientific Interest (SSSI), where management techniques that support the species are in use (7).

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 Plantlife, the wild plant conservation charity, see:
http://www.plantlife.org.uk