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Species profile—Macadamia jansenii


Plantae (plants) → Equisetopsida (land plants) → ProteaceaeMacadamia jansenii

Species details

Plantae (plants)
Equisetopsida (land plants)
Scientific name
Macadamia jansenii C.L.Gross & P.H.Weston
WildNet taxon ID
Alternate name(s)
bulberin nut
Bulburin macadamia nut
Bulburin nut tree
Nature Conservation Act 1992 (NCA) status
Environment Protection and Biodiversity Conservation Act 1999 (EPBC) status
Conservation significant
Pest status
Short Notes
handwriting of author Checked as QLD sensitive after GPG request to Wildnet (PAR 03/10/2019)
Macadamia jansenii is a single or multi-stemmed tree growing 6 to 9 m tall. The bark is smooth and dotted with prominent lenticels. The branchlets are terete, dark brown with scattered white lenticels, and glabrescent. The seedling leaves are opposite for at least seven nodes or occasionally one or two at the base of the lateral shoots, alternate, elliptical for one or two nodes than oblanceolate. The margins on the seedlings leaves are entire or some leaves have 1-10 teeth. The adult leaves are in whorls of 3, growing 10 to 17.5 cm long and 2.5 to 5.0 cm wide. The upper leaf surface is scarcely glossy, and the lower surface is paler. The petiole is 2 to 14mm long; the lamina oblanceolate, the base is attenuate, sometimes cuneate; the margin entire, somewhat undulate; the apex acute to attenuate, mucronate; the midrib is prominent below, inconspicuous above.
The conflorescence is simple; rachis 10 to 17.5 cm long; bract oblong, about 8mm long. The tepals are 7 to 9 mm long, creamy brown. The filaments are about 6.5 mm long, adnate to tepals for 3 to 4.5 mm. The anthers are 1 to 1.8 mm long. The ovary about 1.8 mm long; style 10 to 11 mm long. The fruit is tardily dehiscent, 15 to 25 mm long by 20 to 24 mm wide; pericarp about 2mm thick. The seeds are globose to broadly ovoid, 14 to 18 mm long by 11 to 16 mm wide; testa 0.8 to 1.5 mm thick (Gross and Weston, 1992).
Macadamia jansenii differs from M. ternifolia in having entire lamina margins and creamish brown flowers while M. ternifolia has spinose lamina margins and pink flowers. A major difference between M. jansenii and M. integrifolia and M. tetraphylla is that M. jansenii has small inedible fruit (Gross and Weston, 1992).
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Macadamia jansenii grows in Araucarian microphyll-notophyll vineforest. (Queensland Herbarium, 2012)Canopy species include: Araucaria cunninghamii (hoop pine), Alangium villosum (canary muskheart), Argyrodendron trifoliatum (brown tulip oak), Baloghia inophylla (scrub bloodwood), Brachychiton discolor (scrub bottletree), Dendrocnide photinophylla (shiny-leaved stinging tree) and Harpullia pendula (tulipwood) (Costello et al. 2009). It is found on steep, rocky, hilly terrain at about 350 m above sea level, where it occurs on well drained, red brown, sandy clay loams (Gross and Weston 1992).
Flowers have been observed in July and December (Queensland Herbarium, 2012). It is thought that Macadamia jansenii is pollinated by native bees and seed dispersed by vertebrates (Gross and Weston 1992). Many of the mature individuals are multi-stemmed, suggesting that the species may facultatively resprout in response to fire or the impact of localised flooding (Costello et al. 2009).
Threatening processes
Macadamia jansenii is known from one population in an area that occupies less than a hectare. This makes the species highly susceptible to a single disturbance event (such as fire) or disease. Notwithstanding the effort to date, it also reinforces the need to search for additional populations and establish either a second population or an ex situ gene bank for the species (Costello, et al. 2009). Other threats include inbreeding due to the single population, the movement of self-pollen and resultant reproductive outputs (or lack of) depending on the mating system of the species; wildfire and inappropriate fire regimes (e.g. extended drought conditions exacerbated by rising temperatures may provide the conditions for fire to erode the rainforest mantle that protects the existing population); weed invasion (e.g. lantana is also found in canopy breaks downstream of the source population, but is not currently threatening individual trees; and illegal collection (DSEWPC, 2012).
Status notes
Macadamia jansenii is listed as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 and the Queensland Nature Conservation Act 1992
Management recommendations
Regional and local priority actions to support the recovery of Macadamia jansenii are outlined by DSEWPC (2012). A summary of these include: avoid habitat loss, disturbance and modification (e.g. monitor known populations to identify key threats, monitor the progress of recovery; identify populations of high conservation priority); increase conservation information (raise awareness of Macadamia jansenii in the local community); control invasive weeds (e.g. develop and implement a management plan for control of Lantana in the region); manage fire (develop and implement a suitable fire management strategy for M. jansenii); and enable recovery of additional sites and/or populations (e.g. undertake appropriate seed collection and storage, investigate the options for linking, enhancing or establishing additional populations) (DSEWPC; 2012).
Further management recommendations can be found in Costello et al. (2009).
Occurs in the following Queensland pastoral district: Port Curtis.
Costello, G., Gregory, M. and Donatiu, P. (2009). Southern Macadamia Species Recovery Plan. Report to Department of the Environment, Water, Heritage and the Arts, Canberra by Horticulture Australia Limited, Sydney.
Department of Sustainability, Environment, Water, Population and Communities (DSEWPC) (2012). Macadamia jansenii in Species Profile and Threats Database, Department of Sustainability, Environment, Water, Population and Communities, Canberra.
Gross, C.L. and Weston, P.H. (1992). Macadamia jansenii (Proteaceae), a new species from Central Queensland. Australian Systematic Botany 5, 725-728.
Gross, C.L. in McCarthy, P.M. (Ed) (1995). Flora of Australia 16: 422-423, .
Queensland Herbarium (2012). Specimen label information. Queensland Herbarium. Accessed 19/01/2012.
Profile author
Ronald Booth (01/05/2012)

Other resources

Data source

This profile data is sourced from the QLD Wildlife Data API using the Get species by ID function used under CC-By 4.0.

This information is sourced from the WildNet database managed by the Queensland Department of Environment and Science.

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Last updated
8 March 2022