Pimelea williamsonii

Thymelaeaceae

Williamson's Riceflower

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plant: Pimelea williamsonii BilliatCP post-fire

plant: Pimelea williamsonii BilliatCP post-fire 1

plant: Pimelea williamsonii plant Billiat

seed: Pimelea williamsonii DEM7055 seeds

dissected seed: Pimelea williamsonii DEM7055 Longitudinal cut

dissected seed: Pimelea williamsonii DEM7055 Excised embryo

dissected seed: Pimelea williamsonii DEM7055 Transverse cut

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 painting: 1

Common names

Williamson's Riceflower

Etymology

Greek 'pimele' fat, alluding to the fleshy cotyledons and

Distribution and status

Sandy soils and disturbed sites, often observed post-fire Rare
Herbarium regions: Eyre Peninsula, Murray
AVH map: SA distribution map (external link)

Plant description

Wooly subshrub to 30cm tall. Leaves elliptic, 2.5-16 mm long, 1-5 mm wide, acute to obtuse, lower surface with coarse antrorse white or colourless hairs and the upper surface with fewer and finer hairs. Inflorescence a terminal spike to 6.5cm long. Flowers bisexual, white, 3.5-5 mm long. Flowering most of the year. Seeds are seed ventricose, hooked at the apex, glabrous, black, finely reticulate 1-5mm

Seed collection and propagation

Collect seeds between November and December.

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 MSB	2,100 (1.18 g) 2,100 (1.18 g)	50+	16-Nov-2010	DEM7055 South Eastern	1-Jan-2012	95%	-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
Jun-08	23%	20	NA	after ripening 45Â°C oven 6weeks; 1% agar; Incubated under winter conditions
Jun-08	13%	27	NA	1% agar; Incubated under winter conditions
Jul-11	8%	28	NA	1% agar with 250 mg/L gibberellic acid (pH 6.5); Incubated under winter conditions
Jul-11	2%	56	NA	1% agar with 100 mg/L potassium nitrate; Incubated under winter conditions
Jul-11	2%	28	NA	1% agar with 250 mg/L gibberellic acid (pH 6.5); Incubated under spring/autumn conditions
Jul-11	0%	NA	NA	1% agar with 100 mg/L potassium nitrate; Incubated under spring/autumn conditions
Jul-11	0%	NA	NA	1% agar; Incubated under spring/autumn conditions
Jul-11	0%	NA	NA	1% agar; Incubated under winter 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)

Eyre Hills (EYB03)	Eyre Yorke Block	Vulnerable (IUCN: VU D1+2)
Talia (EYB04)		Vulnerable (IUCN: VU B2ab(i,ii,iii)) (Probable Decline)
Eyre Mallee (EYB05)		Rare (IUCN: RA d(ii))
Murray Mallee (MDD02)	Murray Darling Depression	Vulnerable (IUCN: VU D2) [needs fire or disturbance]
Lowan Mallee (MDD04)		Rare (IUCN: RA d(i,ii)) [highly localised]