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
Display IBRA region text
| Broughton (FLB02) | Flinders Lofty Block | Critically Endangered (IUCN: CR D) |
| Murray Mallee (MDD02) | Murray Darling Depression | Vulnerable (IUCN: VU B2ab(i,ii,iii)) (Probable Decline) [restricted to river; naturally rare] |
| Murray Lakes and Coorong (MDD03) | | Rare (IUCN: RA d(ii)) (Probable Decline) |
| Murray Scroll Belt (RIV06) | Riverina | Vulnerable (IUCN: VU B2ab(i,ii,iii)) (Probable Decline) [restricted to river; naturally rare] |
| Arcoona Plateau (GAW04) | Gawler | Vulnerable (IUCN: VU D1+2) |
Botanical art
Kath Alcock painting: 1.
Etymology
Duma from Latin meaning thorny, referring to the thorn-like branch tips of the Genus . Horrida from the Latin 'horridus' meaning rough, shaggy, prickly, referring to its more irregular and rough appearance than the other species.
Distribution and status
Found along the Murray River in South Australia growing on floodplains and beside dry inland lakes. Also found in New South Wales and Victoria. Native. Rare in South Australia. Rare in Victoria.
Herbarium regions: Gairdner-Torrens, Murray, South Eastern
NRM regions: South Australian Arid Lands, South Australian Murray-Darling Basin, South East
AVH map: SA distribution map (external link)
Plant description
Stiff, divaricately branched but rather open shrub to 1 m high and wide with greyish-brown stems, partly leafless and often with spine-tip. Leaves crowded on very short lateral branches, eventually shed; linear to 50 mm long and 2 mm wide; papery. Inflorescence in axillary or nodal clusters with small, green or yellowish flowers. Flowering between March and October. Fruits are green-brown angular-tuberculate, 4-sided fruit. Seeds are shiny dark brown to black ellipsoid to ovoid seed to 2.5 mm long and 2 mm wide. Seed embryo type is peripheral.
Seed collection and propagation
Collect seeds between July and December. Collect ripping fruits that are turning brown and containing a hard brown to black seed. Mature fruits will come off easily. Place fruits in a tray and leave to dry for 1-2 weeks. Then rub the fruit with a rubber bung to dislodge the seeds. use a sieve to separate unwanted material. Then store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place. This species has intermediate to deep physiological dormancy.
| Location | No. of seeds
(weight grams) | Number
of plants | Date
collected | Collection number
Collection location | Date
stored | % Viability | Storage
temperature | | BGA | 2,200 (18.76 g) | 25 | 19-Oct-2011 | DJD2296
Murray | 1-Nov-2012 | 100% | -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.
Germination table:
Display
| Date | Result | T0 | T50 | Pre-treatment | Germination medium | Incubator: Photoperiod / Thermoperiod |
| Jun-13 | 96% | 24 | 24 |
seeds excised from fruit, 400mg/L gibberellic acid 3 d;
1% agar;
Incubated under spring/autumn conditions |
| Jun-13 | 32% | 14 | NA |
seeds excised from fruit;
1% agar;
Incubated under spring/autumn conditions |
| Jun-13 | 4% | 24 | NA |
leached in water 3 d;
1% agar;
Incubated under spring/autumn conditions |
| Jun-13 | 0% | NA | NA |
1% agar;
Incubated under spring/autumn conditions |
Result: Maximum percentage of germination observed.
T0: Number of days before first germinant observed.
T50: Number of days to achieve 50% germination.
Pre-treatment: The initial treatment that the seeds received prior to placement on germination media.
Germination medium: The substrate that seeds were placed on for the duration of the germination experiment.
Incubator conditions:
Photoperiod: The duration of light exposure that the seeds were subject to during a 24 hour period.
Thermoperiod: The constant or diurnal temperatures that seeds were subject to during a 24 hour period.
Winter conditions: 15°C 20 h (3am→11pm); 5°C 4 h (11pm→3am) / 10 h light (8am→6pm); 14 h dark (6pm→8am)
Spring/Autumn conditions: 22°C 12 h (8am→8pm); 10°C 12 h (8pm→8am) / 12 h light (8am→8pm); 12 h dark (8pm→8am)
Summer conditions: 30°C 14 h (6am→8pm); 15°C 10 h (8pm→6am) / 14 h light (6am→8pm); 10 h dark (8pm→6am)
