STUDIES ON THE INSECT FAUNA ON BCOTCE BROOM
89
If. DESCRIPTZON O F THE AREA O F STUDY A N D OF
T H E HOST PLANT
A. SILWOOD P A E K ABEA
Silwood Park is situated about 1.6 km on the London side of Ascot,
Berkshire, 61"24'N and 0'34'W on an altitude of 61 m. It lies in that
part of England which has the nearest approach to a continental
climate, having relatively hot dry summers and cold winters. Much of
the area of approximately 97 hectares w w at one time included within
Windsor Great Park, but part of the grounds has been cultivated or
haa formed part of a garden for hundreds of years. The underlying
geology ia Eocene, namely Bracklesham beds (gravel, sand and some
clay) on the east and on Bagshot sands (sand with gravel) on the rest
of the area. Much of the higher ground, including all the Bracklesham
beds is capped with Plateau gravel, incorporating much clay in some
areaa, but the soils are nearly always very light. The soils dry out very
rapidly after rain, the water table in summer is well below the surface
(Waloff and Blackith, 1962) and the vegetation tends to suffer during
droughts. The greater part of the area is covered by acid grassland of
rather uniform type, dominated by Festuca rubra L., Agrostis tenuis
Sibth. with patches in which Holcus mollis L. forms closed stands. There
are three main areas of woodland with much beech (Fagus) and oak
(Quercus ruber L.) and a number of exotica (Rhododendron, Abies,
Quercw cerria L., etc.). Locally there are small patches of Erica
cinerea L., Calluna vulgario L. and Pteridium aquilinum (L.) forming
true heathland which may once have been more extensive.
B. Sardhamnw smpariw (L.) WIMMER
1. T h phnt
Broom is widely distributed in the British Isles (absent in Orkney
and Shetland) and is found especially on disturbed mils. Its European
distribution stretches from southern Scandinavia to Spain and the
Canary Islands, but it does not extend eastwards beyond Poland and
Hungary in Central Europe (Clapham et al., 1967). It grows in abundance on the hills around the north of Rome. Meusel et al. (1965) give a
map of its distribution and say that it has run wild in some submediterrancan areas, for instance near Sarajevo in Yugoslavia, in
Romania as well as on the Nilghiri hills in India. It has been introduced,
sometimea inadvcrtently, into S.W. Australia, New Zealand, into the
eastern United States and the Pacific Northwest from California to
British Columbia. In California it has flourished and has become a weed
on arable and forest lands and measures me now taken to control ib..
spread (see Holloway in Doutt and DeBach, 1964).
89
If. DESCRIPTZON O F THE AREA O F STUDY A N D OF
T H E HOST PLANT
A. SILWOOD P A E K ABEA
Silwood Park is situated about 1.6 km on the London side of Ascot,
Berkshire, 61"24'N and 0'34'W on an altitude of 61 m. It lies in that
part of England which has the nearest approach to a continental
climate, having relatively hot dry summers and cold winters. Much of
the area of approximately 97 hectares w w at one time included within
Windsor Great Park, but part of the grounds has been cultivated or
haa formed part of a garden for hundreds of years. The underlying
geology ia Eocene, namely Bracklesham beds (gravel, sand and some
clay) on the east and on Bagshot sands (sand with gravel) on the rest
of the area. Much of the higher ground, including all the Bracklesham
beds is capped with Plateau gravel, incorporating much clay in some
areaa, but the soils are nearly always very light. The soils dry out very
rapidly after rain, the water table in summer is well below the surface
(Waloff and Blackith, 1962) and the vegetation tends to suffer during
droughts. The greater part of the area is covered by acid grassland of
rather uniform type, dominated by Festuca rubra L., Agrostis tenuis
Sibth. with patches in which Holcus mollis L. forms closed stands. There
are three main areas of woodland with much beech (Fagus) and oak
(Quercus ruber L.) and a number of exotica (Rhododendron, Abies,
Quercw cerria L., etc.). Locally there are small patches of Erica
cinerea L., Calluna vulgario L. and Pteridium aquilinum (L.) forming
true heathland which may once have been more extensive.
B. Sardhamnw smpariw (L.) WIMMER
1. T h phnt
Broom is widely distributed in the British Isles (absent in Orkney
and Shetland) and is found especially on disturbed mils. Its European
distribution stretches from southern Scandinavia to Spain and the
Canary Islands, but it does not extend eastwards beyond Poland and
Hungary in Central Europe (Clapham et al., 1967). It grows in abundance on the hills around the north of Rome. Meusel et al. (1965) give a
map of its distribution and say that it has run wild in some submediterrancan areas, for instance near Sarajevo in Yugoslavia, in
Romania as well as on the Nilghiri hills in India. It has been introduced,
sometimea inadvcrtently, into S.W. Australia, New Zealand, into the
eastern United States and the Pacific Northwest from California to
British Columbia. In California it has flourished and has become a weed
on arable and forest lands and measures me now taken to control ib..
spread (see Holloway in Doutt and DeBach, 1964).