Click on images to enlarge
infestation (Photo: Rob and Fiona Richardson)
habit prior to flowering (Photo: Rob and Fiona Richardson)
habit in flower (Photo: Rob and Fiona Richardson)
lower leaves, with deeply-lobed margins (Photo: Rob and Fiona Richardson)
upper leaves and flower-heads (Photo: Rob and Fiona Richardson)
flower-heads with spiny floral bracts (Photo: Rob and Fiona Richardson)
close-up of flower-head (Photo: Rob and Fiona Richardson)
Scientific Name
Berkheya rigida (Thunb.) Ewart, Jean White & B. Rees
Synonyms
Stobaea rigida Thunb.
Family
Asteraceae (Queensland, New South Wales, the ACT, Victoria, Tasmania, Western Australia and the Northern Territory)Compositae (South Australia)
Common Names
African thistle, berkheya, berkheya thistle, Augusta thistle, Hamelin thistle
Origin
Native to southern Africa (i.e. Cape Province in South Africa).
Naturalised Distribution
Naturalised in some parts of southern Australia (i.e. in the coastal districts of south-western Western Australia, in Tasmania, in southern and western Victoria and in southern South Australia). This species in not yet widely distributed in Australia and is mostly represented by scattered infestations. In Tasmania it has only been reported from King Island in Bass Strait, and these populations are thought to have been eradicated.
Notes
African thistle (Berkheya rigida) is regarded as a minor or potential environmental weed in Victoria, Tasmania and Western Australia. It is a weed of sandy sites and pastures that can be locally abundant, particularly in coastal environs. It spreads via creeping underground stems and can form large colonies. This species is thought to have been introduced from South Africa in ships ballast many years ago.
African thistle (Berkheya rigida) is thought to pose a potential threat to one or more vegetation formations in Victoria, and is listed as an environmental weed in the Mornington Peninsula Shire. It has also been recorded growing in reasonably intact native vegetation in south-western Western Australia (e.g. in coastal areas near Augusta).
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