Acacia brachybotrya

Grey Mulga, Grey Wattle at Watson, ACT

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Identification history

Acacia brachybotrya	14 Jun 2023	abread111
Acacia brachybotrya	14 Jun 2023	WalterEgo
Acacia buxifolia subsp. buxifolia	13 Jun 2023	CarbonAI
Acacia buxifolia subsp. buxifolia	13 Jun 2023	WalterEgo

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10 comments

waltraud wrote:

14 Jun 2023

Grey Mulga is not a local species. Canberra Nature can you please correct this?
The Grey Mulga we find on the northwest slope of Mt Majura are recruits from the Federal Highway plantings. Sam, one difference between A buxifolia and A brachybotrya is that the former has its globular flower heads on a raceme and the latter on axillary peduncles, either as a singular flower head or a couple on a very short common stalk as shown on your photograph.

Tapirlord wrote:

14 Jun 2023

Corrected for our local region.

abread111 wrote:

14 Jun 2023

Ciaran,
Not sure you should have changed its status. Could just be an outlier on the eastern margin of its distribution. No evidence that it was planted on the Federal Highway - do you have any evidence?

abread111 wrote:

14 Jun 2023

Hi Wal Re Acacia brachybotrya, please discuss with Isobel before you assume it is spreading from a planting on the highway. I have looked at its distribution on ALA and I don't think you can assume it is not just the eastern most outlier in a natural distribution. If it was planted on the Federal Highway, it was spectacularly unsuccessful. Last spring Max walked along a fair way on the highway verge last spring and found none, and Greg Baines found one at the same time that Max found the one in the reserve. There is one herbarium specimen from the highway embankment in 1998 where Max walked. The other occurrences on ALA on the eastern fringe of its distribution tend to be in reserves (where people are looking at the veg) and very few and mostly from years ago. It may be a case like Goodia lotifolia where Mt M is the western edge of its distribution. Barb

waltraud wrote:

14 Jun 2023

Barb thank you for your message reg the status of this species
To my knowledge ALA shows records of species but not their natural distribution, see for instance Acacia baileyana: https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2915203
The ALA most eastern isolated record of A. brachybotris in Canberra represents in my view a doubtful natural distribution.
I still use Leon Costermans when I check trees and shrubs and his given natural distribution of A. brachybotris confirms ALA profile of A brachybotrya which states for the Distribution: "Widely distributed in semi-arid areas of south eastern Australia from the Murray River, South Australia, E to near Bendigo, Victoria and N to Nymagee, New South Wales.... Habitat: Occurs on a variety of soils, often in mallee communities." See https://profiles.ala.org.au/opus/foa/profile/Acacia%20brachybotrya
also see NSW PlantNET: https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Acacia~brachybotrya

waltraud wrote:

14 Jun 2023

I'll discuss with Greg B., Isobel C. and Rosemary P.

Tapirlord wrote:

14 Jun 2023

Barbara i have changed the status, If you look at the CNM species information you will see it now lists this species as non-local native. Even as a global moderator I don't have the ability to change the listing and nor do I think we should as this species will be native in nearly every region it is recorded in.

I would again make the point that I think its unlikey for this species to be antive to the ACT, as it is otherwise associated with mallee country of NSW, Vic and SA. Mt Majura doesn't provide anything like typical habitat and so I think we should assume it is not local to our area (whether or not you should remove it is a different question). ACT native the Acacia species are actually quite well known, we have 22 local species. I can provide the list if it would be useful.

It is interesting that you mention a herbarium collection as Acacia brachybotrya is not on the census, which it should be if collected in the ACT in 1998. I don't think we can draw conclusions from this but its certainly interesting. I'd actually liken this to Maireana microphylla in the ACT, which has only been recorded from the site of a former abattoir. So perhaps these ACT plants orginated from seed brought in with stock or feed. The other point to make is that this would be a very significant extension in terms of national distribution, if the population is local.

In terms of Goodia lotifolia, Mt Majura is not the only ACT location. It has also been recorded in the montane forests of Tidbinbilla and the upper cotter which matches up with other disjunct populations like those in Tallangada. That species spreads easily from seed much like Cassinia and seems to favour disturbed sites (hence Majura pines).

waltraud wrote:

14 Jun 2023

thanks, Barb and Ciaran
Barb, the 1998 specimen that you mentioned is most likely from plantings along Fed highway; also Greg B's 2022 sample is from the Fed highway. Unfortunately, there seems to be no list of species that were planted there. The fact it doesn't recruit well may reflect its natural habitat requirements (other than Snowy River wattle and Knife-leaved wattle which invade heavily from the Fed highway plantings). It might be that the records of A brachybotrya on the ALA stem from planted and subsequently recruited specimens.
Goodia. I found Goodia lotifolia in the Nadgee wilderness last summer (I should load up my photos) where it seemed to have responded to the 2019/20 fire. I think to remember that Isobel told me when we discussed Goodia lotifolia, it was found in Tidbinbilla after fire in the 1950's, see the distribution map with the 1957 record. So this seems a case where a local species with seeds of lang viability respond to a fire and the opening of the landscape. In reg to Mt Majura I think the pine plantation on the east slope was first established in 1950's, burned in the 1985 big fire (which burned most of Mt Majura and started in the pine plantation on the east slope), and corridors on the east slope were cut in 2014 (? can be checked with Google Earth); the Goodia seeds seemed to have survived and might have been unrecognized germinated and recruited after the 1985 fire and then again - this time recognized - after the disturbance and opening up when the pine trees were removed. So, here I agree, that Goodia lotifolia occurs naturally in the ACT and its source is unlikely from plantings.
Some species are a real puzzle!

waltraud wrote:

14 Jun 2023

forgot: I agree with Ciaran a non-local status does not automatically mean the species should be removed if it doesn't become invasive ...

abread111 wrote:

14 Jun 2023

The other eastern fringe sightings on ALA for grey mulga are not in mallee country either and in locations where they are not likely to have been planted eg record DNA D0013868 NW of Cowra in 1977, NSW412896 from near Weddin Mountains National Park in 1982, BRI AQ0168180 from The Mullions Range, 14 miles (22.5km) NNE of Orange in 1972, NSW:NSW372407 from Victoria near Albury in 1898.
The earlier 1998 collection from near the Federal Highway is in a Melbourne herbarium MEL:MEL 2105911A https://biocache.ala.org.au/occurrences/1dd29a4a-21c2-4296-9658-6c7b7c2b327a

In Victoria it is described as "growing in a variety of soils, in mallee communities on sandy loam soils, or in taller woodland on more fertile loams"

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