Orobanche alba, also known by its common names thyme broomrape
It is native to countries across Europe, the Middle East, Asia, and North Africa. As Orobanche alba is polymorphic and has been relatively poorly studied, there is often uncertainty over taxonomy and classification.
Description
Orobanche alba is a short reddish annual with simple flowering stems.
They grow between tall.
Plants have fragrant flowers, cylindrical
campanulate (bell-shaped)
petal with dark glands, and calyx teeth which are usually '' (consisting of a single piece).
The plant generally flowers from May to June (though in rare cases it flowering can occur into early September) and is pollination by bumblebees.
Subspecies
Orobanche alba has four accepted infraspecific names:
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Orobanche alba subsp. alba: Originally described as Orobanche rubra.
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Orobanche alba subsp. cuprea: First reported in 1879 by Pierre Edmond Boissier and Benjamin Balansa, it was originally described as a separate species Orobanche cuprea.
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Orobanche alba subsp. major: First described in 1871 by Ladislav Josef Čelakovský as a separate species, Orobanche epithymum.
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Orobanche alba subsp. xanthostigma: Described in 2004 by Stefan Rätzel and Holger Uhlich. Orobanche alba subsp. xanthostigma differs due to having consistently yellow stigma, free calyx segments, and differing filaments.
[ The form typica has more or less normal colouring whereas for the form sineglandulosa the whole plant is "wax-like yellow" and with less visible glandules.]
A study published in Acta Biologica Cracoviensia found that molecular tests "did not clearly explain" the relationships between O. alba subsp. alba and O. alba subsp. major and suggested that they should be considered forms of O.alba rather than subspecies.
Habitat
Orobanche alba is usually found on dry sunny slopes,
, subalpine and
alpine meadows, growing in calcareous, alkaline, sandy or loamy soil.
It parasitises plants from Lamiaceae.
Distribution
Africa
Orobanche alba can be found in north-west Africa and is native to
Morocco and
Algeria.
Asia
Orobanche alba is native to countries throughout the
Middle East and
Asia including
Turkey,
Iraq,
Iran,
Afghanistan,
Pakistan and parts of
China.
Europe
Orobanche alba is found across Europe,
including in
Ireland, southern
Belgium, central
Germany, the island of
Gotland and south eastern
Poland.
O. alba is "locally abundant" on Sicily, occurring on the mountains on the north coast from Monte Erice to Monte Catalfano, on Mount Etna, and on the Nebrodi and Peloritani ranges as well as inland near Ciminna.
United Kingdom
In the United Kingdom,
O. alba has been found most commonly in
Cornwall (especially near
Kynance Cove),
,
Northern Ireland and particularly prolifically in western
Scotland.
It is also present in the west of Ireland.
The highest record was made at Nappa Scar,
Wensleydale at around .
Populations are said to vary significantly from year to year, but overall appear stable; however numbers in northern England have become "consistently ... critically low".
The 2014 Red List for England rated
Orobanche alba as "Least Concern" over the period 1930 to 1999, but noted a 59% decline in records since 1987 when pre-1930 historic sightings were included.
