Pedunculate sea-purslane (Atriplex pedunculata)

Also known as:	Stalked orache

Kingdom	Plantae
Phylum	Anthophyta
Class	Magnoliopsida
Order	Caryophyllales
Family	Chenopodiaceae
Genus	Atriplex (1)
Size	Height: up to 50 cm (2)

Classified as Critically Endangered in Great Britain and fully protected by Schedule 8 of the Wildlife and Countryside Act, 1981 (3).

Pedunculate sea-purslane is an erect, branching shrub, with fleshy leaves arranged alternately on the stem. The flowers are small, and male and female flowers occur on separate plants. The fruits are attached to the plant by short stalks, unlike sea-purslane (A. portulacoides), which has fruits without stalks (2).

This species was believed to have become extinct by the 1930s. However, it was re-discovered in 1987 in Essex. Historically it has been recorded from East Kent, Lincolnshire and Suffolk (3). Elsewhere this plant occurs in Europe from the north of France to Estonia. It also occurs in areas of western Asia and in the vicinity of the Black Sea. The species is in decline throughout this range and has suffered local extinctions (3).

Typical habitats in the UK that have supported this plant are disturbed areas of salt marshes or grazing marsh. Patches of bare ground are essential in order for the seeds to germinate successfully (3).

This plant germinates in spring, flowers in August and produces fruit in September and October. The number of plants at a site tends to vary greatly each year, and the species is a relatively poor coloniser of suitable habitat (3). The main European stronghold of pedunculate sea-purslane is on the Danish Coast, and it is possible that the species was introduced to Essex by geese or other migratory birds, which pass through Denmark when the seeds are ripening (3).

In 1994 an identified threat to the species was competition with sea couch, Elytrigis atherica and red fescue grass, Festuca rubra (3).

An ex-situ population has been established at Cambridge Botanic Garden, and a population was established in the wild in 1989 at Foulness Island using material from the captive stock. This colony was accidentally destroyed, but other reintroductions have taken place in Essex. Active management at these sites has aimed to keep sea couch and red fescue in check (3). An unfortunate note to end upon is that in 1995 and 1996 the species was absent from the original site, and was only found at sites where it had been introduced (3). This highlights the importance and value of establishing captive stocks for reintroductions; they provide a last-ditch defence against species extinction.

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

• Colonise: establish a colony (group of organisms living together).
• Colony: a group of organisms living together, individuals in the group are not physiologically connected and may not be related, such as a colony of birds. Another meaning refers to organisms, such as bryozoans, which are composed of numerous genetically identical modules (also referred to as zooids or ‘individuals’), which are produced by budding and remain physiologically connected.
• Ex-situ: measures to conserve a species or habitat that occur outside of the natural range of the species. E.g. in zoos or botanical gardens.

1. National Biodiversity Network Species Dictionary (September, 2002)
   http://www.nhm.ac.uk/nbn/
2. Press, B. and Gibbons, B. (1993) Photographic field guide: Wild Flowers of Britain and Europe. New Holland Ltd., London.
3. Wigginton, M.J. (1999) British Red Data Books 1; Vascular Plant. 3rd Edition. Joint Nature Conservation Committee, UK.