Brachyscome dichromosomatica var. dichromosomatica

Asteraceae

Purple Hard-head Daisy,

Large Hard-head Daisy

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plant: Brachyscome dichromosomatica var dichromosomatica habitat

fruit: Brachyscome dichromosomatica var dichromosomatica (2)

seed: Brachyscome dichromosomatica var. dichromosomatica KHB530 seed

seed: Brachyscome dichromosomatica var. dichromosomatica KHB530 seeds

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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Prior names

Brachycome lineariloba

Brachycome dichromosomatica var. dichromosomatica

Common names

Purple Hard-head Daisy

Large Hard-head Daisy

Etymology

Brachyscome from the Greek 'brachys' meaning short and 'kome' meaning hair; referring to tuft of short bristles or hairs of the pappus. Dichromosomatic meaning having two chromosomes.

Distribution and status

Endemic to South Australia and found in the Flinders Ranges and Lake Torrens region, growing saltbush, arid low shrubland and on rocky outcrops. Native. Common in South Australia.
Herbarium regions: Lake Eyre, Gairdner-Torrens, Flinders Ranges, Eyre Peninsula
AVH map: SA distribution map (external link)

Plant description

Annual herb to 25 cm high. Leaves basal and near-basal, not forming a rosette, pinnatisect with 5-9 linear obtuse segments, 3-8 cm long, glabrous. Yellow daisy flower appearing in June to September. Brachyscome dichromosomatica var. dichromosomatica differ from B. dichromosomatica var. alba by having pale blue or mauve ray corolla, at least on the under surface (white ray corolla in B. dichromosomatica var. alba). Fruits are dense brown daisy-heads. Seeds are brown-black wedge-shaped seed 3 mm long and 1 mm wide, with dense long white hairs along the margin. Seed embryo type is spatulate fully developed.

Seed collection and propagation

Collect seeds between August and December. Pick heads that are maturing, drying off, with brown seeds. Place the seed-heads in a tray and leave to dry for a week. Then gently rub the heads with a rubber bung to dislodge the seeds. Use a sieve to separate the unwanted material. 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. From one collection, the seed viability was high, at 100%. This species has physiological dormancy that need to be overcome for the seed to germinate.

Seeds stored:

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Location	No. of seeds (weight grams)	Number of plants	Date collected	Collection number Collection location	Date stored	% Viability	Storage temperature
BGA	18,000 (12.58 g)	100+	23-Nov-2010	KHB530 Flinders Ranges	1-Jan-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:

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Date	Result	T0	T50	Pre-treatment \| Germination medium \| Incubator: Photoperiod / Thermoperiod
May-11	100%	13	20	1% agar with 100 mg/L potassium nitrate; Incubated under winter conditions
May-11	100%	13	20	1% agar with 250 mg/L gibberellic acid (pH 6.5); Incubated under winter conditions
May-11	100%	13	20	1% agar; Incubated under winter conditions
May-11	34%	13	NA	1% agar with 250 mg/L gibberellic acid (pH 6.5); Incubated under spring/autumn conditions
May-11	30%	13	NA	1% agar; Incubated under spring/autumn conditions
May-11	25%	13	NA	1% agar with 100 mg/L potassium nitrate; 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)

Olary Spur (FLB03)	Flinders Lofty Block	Data Deficient [Edge of range]
Southern Flinders (FLB04)		Least Concern
Northern Flinders (FLB05)		Rare (IUCN: RA d(i,ii)) [can be confused with other spp]
Central Flinders (FLB06)		Rare (IUCN: RA d(i,ii)) (Probable Decline) [habitat degraded; grows red loamy soils]