Plants of
South Australia
Choretrum spicatum ssp. spicatum
Santalaceae
Kangaroo Island Spiked Sour-bush
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Rare
Vulnerable
Endangered
Critically endangered
Extinct
Data deficient
Adelaide
Arkaroola
Ceduna
Coober Pedy
Hawker
Innamincka
Marla
Marree
Mount Gambier
Oodnadatta
Renmark
Wudinna
Keith
Yunta
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Botanical art

Kath Alcock paintings: 2.

Etymology

Choretrum from the Greek 'choris' meaning separate and 'etron' meaning abdomen, referring to a rim that separates the top of the flower stalk from the flower itself. Spicatum from the Latin 'spica' meaning a spike, alluding to the flowers forming along a spike.

Distribution and status

Endemic to South Australia and restricted to the western end of Kangaroo Island, growing mainly in heath on sandy laterite soils, often associated with winter inundated flats and shallow open gullies adjacent creeks. Native. Rare in South Australia.
Herbarium region: Kangaroo Island
NRM region: Kangaroo Island
AVH map: SA distribution map (external link)

Plant description

An erect semi-parastic perennial, green shrub to 1.5 m high with rigid and woody branches, terete, longitudinally ridged. Leaves persistent, scale-like, sessile; spreading-ascending to spreading or recurved. Inflorescence of single peduncle bearing many flowers. Flowers white. Fruits are green-brown globose fleshy drupe to 5 mm long, with longitudinal ribs Seeds are woody globular seed to 4 mm long and 3 mm wide, with deep vertical striation. Seed embryo type is linear under-developed.

Seed collection and propagation

Collect seeds between December and March. Collect drupes that are maturing; the skin softens as it ripens. Either collect the drupes from the bushes or collect ripe fruits that have fallen off the plant onto the ground beneath the bushes. Place the drupes in a bucket of water and rub the flesh off with your hands. Drain the water and wash again if required to remove all the flesh. Then spread the wet seeds on paper towel. This species is generally difficult to germinate, it has morpho-physiological dormancy and complex germination requirements.

Fire response

Re-seeder, tiny terete-stemmed seedings proximal or emerging under burnt plants. No burnt shrubs observed re-sprouting.

Longevity: <20 years

Time to first flowering: 4 years.

Recovery work

In 2020 this species was assessed in the first year post-fire. A total of 1,300 seeds were collected from a small population in unburnt remnant vegetation. Germination screening testing fire cues will be undertaken in 2021. This project work is supported by the Australian Government through the Wildlife & Habitat Bushfire Recovery program.

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
 
MSB

1,900 (51.8 g)
20+10-Mar-2006KHB60
South Eastern
BGA152 (1.72 g)716-May-2017MH37
Kangaroo Island
30-Jun-201830%-18°C
BGA138 (1.06 g)2024-May-2017MH39
Kangaroo Island
30-Jun-201820%-18°C
BGA530 (6.73 g)16-May-2017MH38
Kangaroo Island
30-Jun-201846%-18°C
Location: BGA — the seeds are stored at the Adelaide Botanic Gardens, MSB — the seeds are stored at the Millennium Seed Bank, Kew, England.
Number of plants: This is the number of plants from which the seeds were collected.
Collection location: The Herbarium of South Australia's region name.
% Viability: Percentage of filled healthy seeds determined by a cut test or x-ray.