Seeds of South Australia
Olearia arckaringensis (Compositae)
Arckaringa Daisy
List of species for Olearia
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Seed collecting:
October to December
Herbarium region:
Lake Eyre
NRM region:
South Australian Arid Lands
IBRA region
Breakaways (STP01)Stony Plains
 Endangered   (IUCN: EN B2ab(i,ii))   (Probable Decline)   [grazed occasionally; endemic to 2 locations, relict populations; very localised]
RSCA map:
Regional Species Conservation Assessments per IBRA subregion. Please click the thumbnail map.
AVH map:
Australian distribution map (external link)
SA Census:
Census of South Australian plants (external link)     [genus Olearia]
Name derivation:
Olearia named after Johann Gottfried Ölschläger (1603-1671), 17th century German horticulturist and author of a flora of Halle in Germany (his name was latinized to Olearius). Alternatively, it maybe from the Latin 'olearius' pertaining to oil, from 'olea', for olive tree; alluding to the first named species resembling the olive. Arckaringensis named after the location where the species is found, Arckaringa Hills. This name is thought to have been derived from an Aboriginal name, but origin and meaning is not known.
Distribution:
Endemic to South Australia and found only in the Arckaringa Hills, growing in soft, eroding upper slopes of a dissected breakaway escarpment on powdery orchre-coloured gravel and gypsum crystals.
Status:
Native. Very rare in south Australia.
Plant description:
Small, compact long-lived perennial shrub to 30 cm high with a woody base and white-woolly stems aging to grey. Leaves elliptic top 27 mm long and 16 mm wide, greyish-white to light greenish-grey, coarsely serrated, undulated. Inflorescence solitary at terminal with large, lavender (occasionally white) daisy flower. Flowering between September to November.
Fruit type:
Large fluffy white head.
Seed type:
Brown obovoid seed to 2.5 mm long and 0.6 mm wide, covered with scattered short white hairs and long barbed pappus.
Embryo type:
Spatulate fully developed.
Seed collecting:
Collect heads that are large and fluffy. Either pick off the whole heads or use your finger and pull off the seeds from the head. Mature seeds will come off easily.
Seed cleaning:
Place the heads in a tray for a week to dry. No cleaning is required if only pure seeds are collected. If heads are collected, then rub the heads gently with your hands to dislodge the seeds. Viable seeds will be fat and hard. 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.
Seed viability:
From two collections, the seed viability was high, ranging from 91% to 100%.
Seed germination:
Seeds are non-dormant, viable seed should germinate readily.
Seeds stored:
LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
3500 (1.15 g)
3100 (1 g)
100+7-Oct-2010DJD1886
Lake Eyre
1-Jan-2012100%+5°C, -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:
DateResultT0T50Pre-treatment | Germination medium | Incubator: Photoperiod / Thermoperiod
May-17100%77 500 mg/L gibberellic acid for 24 h;
1% agar;
Incubated under winter conditions
May-1796%714 500 mg/L gibberellic acid for 24 h;
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)