Where did they come from?
It is interesting surmising and perhaps trying to work out what populations the various invasive species came from in Australia.
Looking at all the 1500+ observations on iNaturalist of species that are in the Hakea Sericea Group, it is obvious that the South African populations of Hakea sericea arose from a different place to the New Zealand populations. The South African populations have leaves that approach those of Hakea decurrens - being more rigid and with a sharper, more persistent mucro, and tend to be at a broader angle to the stem than the New Zealand populations which appear to have longer, more flexible leaves with a less pronounced mucro and are more acutely arranged on the stems. The New Zealand populations appear to flower and fruit more heavily than the South African populations, but that may be climate related rather than genetic.
Until we have many more measurements of the flowers as well as the leaves, mucro, etc. we will not be able to determine anything for sure. DNA testing of the various populations would also help.
With what we are now assuming to be Hakea decurrens subsp. physocarpa in Portugal and perhaps France (depending on more observations and observations with measurements) - it appears that they are not lignotuberous which indicates that they may have come from an area either near the Grampians or the Brisbane Ranges in Victoria, but more work on the Australian populations are needed to determine the distributional extent of lignotubers for the subspecies in Australia.
So - get out there and start measuring people.
Arthur
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I understand that there may be some information available about the original populations brought to South Africa. Anything to add @tonyrebelo?
@mferreira Do you have any information on why Hakeas were introduced into Portugal and when? Were they for hedges or security hedges as in South Africa or are they escapees from garden cultivation? What is the earliest published occurrence?
A quick, rough look on GBIF for Portuguese specimens, it would appear that there are records from 1938, 1940, 1941, 1954, 1965, 1966, 1972 and later
I just found a paper that states that H. sericea was introduced into South Africa in 1858 and into Portugal in the 1930s as a hedge plant. See https://onlinelibrary.wiley.com/doi/10.1111/epp.12527
Yes: in South Africa we have a very good record of introductions and the alien situation is well researched and extensively reviewed.
Four species of Hakea were introduced as hedges - three as security hedges (H, drupacea, H gibossa, H. sericea - locally known as Needlebushes) and one as windbreaks (H. salicifolia - known as Mak Hakea as it did not spread (mak=tame) - until it went AWOL in the 1990s), probably as part of a KEW initiative to exchange useful plants amongst the commonwealth. But probably more were experimented with. If other species were tested, they were not widely disseminated or used, or documented. Note that any Australian plants en route to KEW stopped at Cape Town and interest in firewood, screens and timber species was intense: indigenous trees in the Cape are not fire tolerant and wood was in very short supply since 10 years after Van Riebeeck established the Cape colony in 1652.
Only H. sericea has been the focus of biocontrol measures, and most biocontrol species have been species specific so dont even affect the other invasive Hakea species.
But while we may have a date for introduction to Europe, the identity of the plant is at question. And your reference states:
In Spain - in Galicia: date?. In France - Alpes Cote, Esterel Mountains - recorded 1917. This is before the reported Portuguese introduction. The identity of these also needs to be confirmed.
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