Plants of
South Australia
Pycnosorus globosus
Compositae
Round Billy-buttons
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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

Pycnosorus from the Greek 'pyknos' meaning dense or thick and 'soros' meaning heap, referring to the dense flowering heads of the genus. Globosus from the Greek 'globolus' meaning spherical, referring to the shape of the compound heads.

Distribution and status

Found in the Flinders Ranges and the mid-north in South Australia, growing in open moist heavy soils prone to inundation. Also found in Queensland, New South Wales and Victoria. Native. Very rare in South Australia. Common in the other states.
Herbarium regions: Lake Eyre, Flinders Ranges, Eyre Peninsula, Northern Lofty, Murray
NRM regions: Adelaide and Mount Lofty Ranges, Eyre Peninsula, South Australian Murray-Darling Basin
AVH map: SA distribution map (external link)

Plant description

Erect perennial herb with few unbranched stems covered in dense white woolly hairs, to 100 cm high. Leaves linear to linear-lanceolate to 30 cm long and 12 mm wide, acute, gland-tipped, both surfaces with appressed white- to grey hairs. Inflorescence a single globose compound yellow head to 35 mm diameter. Flowering between September and December. Fruits are dense pale globular heads with numerous seeds. Seeds are brown ovoid seed to 2.5 mm long and 1 mm wide, covered in long golden hairs. Seed embryo type is spatulate fully developed.

Seed collection and propagation

Collect seeds between November and December. Collect heads that are drying off, fluffy and turning yellow-white with hard brown seeds. Pick off whole heads or pluck off mature seeds with your fingers. Place the heads in a tray and leave to dry for one to two weeks. Then rub the heads gently by hand 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 two collections, the seed viability were average to high, ranging from 50% to 85%. Seeds are non-dormant, viable seed should germinate readily.

Seeds stored:
  Hide
LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA2,000 (4.17 g)26-Nov-2004K.Brewer
Flinders Ranges
31-Mar-2006N/C-18°C
BGA 
MSB
23,800 (42.8 g)
23,800 (42.8 g)
100+27-Nov-2004DJD52
Flinders Ranges
31-Mar-200685%+5°C, -18°C
BGA630 (0.69 g)30-Dec-2005KHB37
Flinders Ranges
14-Sep-200650%-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.