Orobanche rapum-genistae

Tracheophyta MagnoliopsidaOrobanchaceaeOrobancheOrobanche rapum-genistae

Ecology

A perennial root parasite of leguminous shrubs, especially Ulex europaeus and Cytisus scoparius, but also known to occur occasionally on Genista tinctoria. Its habitat, governed by that of its hosts, is mainly scrub, but hedge banks and track-sides are also favoured. Lowland.

Status

Native

World Distribution

Suboceanic Southern-temperate element.

© G. Toone, IWNHAS

Broad Habitats

Dwarf shrub heath (cover of dwarf shrubs at least 25%)

Light (Ellenberg): 7

Moisture (Ellenberg): 5

Reaction (Ellenberg): 3

Nitrogen (Ellenberg): 2

0

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 4.1

July Mean Temperature (Celsius): 15.7

Annual Precipitation (mm): 890

Life form information

Height (cm): 85

Perennation - primary

Perennial

Life Form - primary

Non-bulbous geophyte (rhizome, corm or tuber)

Woodiness

Herbaceous

Clonality - primary

Little or no vegetative spread

Count of 10km squares in Great Britain: 422

Count of 10km squares in Ireland: 30

Count of 10km squares in the Channel Isles: 4

Atlas Change Index: -0.35

Distribution information

JNCC Designations

NBNSYS0000004173

External Species Accounts

Scarce Atlas Account

Scarce Atlas Account: 

Orobanche rapum-genistae Thuill.

Greater broomrape

Status: scarce

 

This broomrape is a root parasite of leguminous shrubs, especially Cytisus scoparius and Ulex europaeus. Its potential habitats are those of its hosts, namely hedgebanks, and scrubby areas on rough hillsides, but it has become increasingly confined to coastal areas. Its vigour is often increased after burning of the host plants.

It is apparently perennial, as evidenced by the previous year's dead spikes frequently persisting beside the following season's new growth. Reproduction is by seed and although this is very small and wind-dispersed, colonisation of new sites is rare, suggesting that other, as yet unknown, ecological factors play their part. Field observations have shown that through its parasitic life-style it can sometimes reduce the vigour of the host plant, occasionally fatally, and at sites where the latter is restricted, this may lead to the plant's ultimate extinction.

This plant was formerly widespread in the British Isles, when it was probably the most commonly encountered broomrape, but has declined appreciably during the present century and is now most often found to the south and west, often in coastal sites. This suggests a climatic cause for its decline. Although the host plants are still abundant, they are often destroyed by scrub clearance, and this may also have contributed to the reduction. The species probably continued to decline into the 1960s and the severe winter of 1962/3 eliminated several populations. Since then new sites have been discovered at a greater rate than they have been lost, even in Norfolk and Northumbria at the easterly extremities of its range. The great wind of 1987 opened up some afforested areas, allowing heathy scrub to regenerate and this species to reappear. It is almost certainly under-recorded on the western fringe of Britain due to the nature of its habitat. Even in localities where a host is abundant, this broomrape is very local and populations are usually small.

This species is found in the western Mediterranean region, extending northwards in western Europe to Britain. 

Colour variants often occur in the larger populations, with the yellow-flowered forma flavescens Durand (forma hypoxantha G. Beck) being the most frequent.

 

M. J. Y. Foley

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 (236d) Curtis TGF, McGough HN
1988.  The Irish Red Data Book. 1. Vascular Plants. Meusel H, Jäger E, Rauschert S, Weinert E
1978.  Vergleichende Chorologie der zentraleuropäischen Flora. Volume 2. 2 vols. Rumsey F, Headley A
1998.  Are British Orobanche species in decline? The Naturalist. 123:76-85. Rumsey FJ, Jury SL
1991.  An account of Orobanche L. in Britain and Ireland. Watsonia. 18:257-295. Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.