An annual or perennial parasite which grows on the roots of Hedera helix, especially subsp. hibernica, and, rarely, on other cultivated Araliaceae. Its habitat is that of its host and includes coastal cliffs, open rocky woodland, quarries, hedge banks and other similar habitats. Lowland.
Western populations of O. hederae in coastal habitats appear to be stable. In S.E. England it has been recorded with increasing frequency in artificial habitats, including gardens, where it is probably introduced, although the possibility of long-range dispersal of the light seeds cannot always be ruled out.
Light (Ellenberg): 4
Moisture (Ellenberg): 5
Reaction (Ellenberg): 6
Nitrogen (Ellenberg): 5
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 4.9
July Mean Temperature (Celsius): 15.5
Annual Precipitation (mm): 1004
Height (cm): 60
Perennation - primary
Perennation - secondary
Life Form - primary
Life Form - secondary
Clonality - primary
Count of 10km squares in Great Britain: 160
Count of 10km squares in Ireland: 122
Count of 10km squares in the Channel Isles: 11
Atlas Change Index: 0.2
Scarce Atlas Account
Orobanche hederae Duby
O. hederae is a holoparasite of the Araliaceae, possibly restricted as a native to the Atlantic tetraploid cytotype of Hedera helix subsp. hibernica. Its distribution closely reflects that of its host (McAllister & Rutherford 1990). O. hederae is essentially a maritime plant of coastal cliffs, undercliff woodlands and hedgebanks, but extending inland in sheltered sites such as gorges. It is grown as a curiosity and persists in gardens, parklands and cemeteries often at wall bases and under hedges.
It is an annual, or perhaps more frequently perennial, plant, probably reliant on self pollination. It has a longer flowering season than any other British broomrape, from late May to October, and is unique in the asynchronous appearance of plants within populations.
There is no threat to the native populations, and the species is apparently increasing through exploitation of cultivated Araliaceae to the east of its native range. All records on cultivated hosts have been mapped as introductions: some records may be of deliberate introductions and others may result from seed windborne from native sites. Its status in the Kent chalk pits is uncertain.
It is found in western, southern and southern central Europe, reaching its most northerly extent in Ireland. In Majorca, and perhaps elsewhere, it is now largely restricted to man-made habitats. Material thought to be of this species has been recorded as an introduction in North Carolina, USA (Musselman 1982). It is also known as an introduction in South Africa where it had been misidentified as O. minor.
O. hederae is often mistaken for the more frequent O. minor which may also grow on Hedera spp. All specimens reported to be of O. hederae from non-araliacean hosts have proved to be misidentifications. However, Jones (1987) claimed to have raised plants on Trifolium pratense. A yellow variant lacking anthocyanin has been reported on cultivated ivy in Hampshire (Brewis 1990).
F. J. Rumsey
Atlas text references
1988. The Irish Red Data Book. 1. Vascular Plants.
1978. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 2. 2 vols.
1991. An account of Orobanche L. in Britain and Ireland. Watsonia. 18:257-295.
1994. Scarce plants in Britain.