Euphorbia portlandica

Tracheophyta MagnoliopsidaEuphorbiaceaeEuphorbiaEuphorbia portlandica

Ecology

A biennial or short-lived perennial herb, growing in a wide range of coastal habitats. It occurs on cliffs, rocky slopes and steep maritime grasslands overlying many different rock types, and also on shingle and sheltered or semi-fixed sand dunes. Lowland.

Status

Native

World Distribution

Oceanic Southern-temperate element.

Broad Habitats

Light (Ellenberg): 8

Moisture (Ellenberg): 3

Reaction (Ellenberg): 7

Nitrogen (Ellenberg): 3

3

Salt Tolerance (Ellenberg): 3

January Mean Temperature (Celsius): 5.3

July Mean Temperature (Celsius): 15.4

Annual Precipitation (mm): 1060

Life form information

Height (cm): 35

Perennation - primary

Perennial

Life Form - primary

Chamaephyte

Woodiness

Herbaceous

Clonality - primary

Little or no vegetative spread

Count of 10km squares in Great Britain: 148

Count of 10km squares in Ireland: 82

Count of 10km squares in the Channel Isles: 14

Atlas Change Index: -0.09

Distribution information

JNCC Designations

NBNSYS0000003735

Scarce Atlas Account

Scarce Atlas Account: 

Euphorbia portlandica L. 

Portland spurge

Status: scarce

 

 

This species is found in a variety of coastal habitats. It frequently occurs on cliffs, rocky slopes and steep maritime grasslands over a wide range of rocks from chalk and limestone to granite. In coastal grasslands frequent associates include Dactylis glomerata, Daucus carota, Festuca rubra, Holcus lanatus, Jasione montana, Plantago maritima and Scilla verna; on some calcareous cliffs it can also be found with several nationally rare or scarce species including Helianthemum apenninum, Scilla autumnalis and Trinia glauca. It also occurs on shingle, and on sheltered or semi-fixed sand-dunes in vegetation dominated by Ammophila arenaria, Festuca rubra or a mixture of the two. Unlike E. paralias, it is not usually found on the most exposed and mobile dune systems. 

E. portlandica is a biennial or short-lived perennial, flowering from April or May to September. It presumably germinates in the spring. Reproduction is entirely by seed.

The distribution of E. portlandica in Britain has probably changed very little during the present century. However, there may have been a slight contraction of range with its disappearance from several localities in north-western England and southern Scotland. Paradoxically, on the north coast of the Isle of Man E. portlandica is thought to be a recent arrival, having been unrecorded there until 1939 (Allen 1984).

The species is found along the coasts of western Europe from Portugal to France, Britain and Ireland. It is at its northern limit in the British Isles.

 

 

S. J. Leach

PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.

Atlas text references

Atlas (172a)
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.