Seeds of South Australia
Pycnosorus globosus (Compositae)
Round Billy-buttoms
List of species for Pycnosorus
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Seed collecting:
November to December
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
IBRA region
Broughton (FLB02)Flinders Lofty Block
 Endangered   (IUCN: EN C2a(i))   (Probable Decline)
Olary Spur (FLB03) 
 Endangered   (IUCN: EN C2a(i))   (Probable Decline)
Southern Flinders (FLB04) 
 Endangered   (IUCN: EN C2a(i))   (Probable Decline)
Central Flinders (FLB06) 
 Vulnerable   (IUCN: VU D2)   [edge of range; not well protected, grazed]
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 Pycnosorus]
Name derivation:
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.
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.
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.
Fruit type:
Dense pale globular heads with numerous seeds.
Seed type:
Brown ovoid seed to 2.5 mm long and 1 mm wide, covered in long golden hairs.
Embryo type:
Spatulate fully developed.
Seed collecting:
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.
Seed cleaning:
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.
Seed viability:
From two collections, the seed viability were average to high, ranging from 50% to 85%.
Seed germination:
Seeds are non-dormant, viable seed should germinate readily.
Seeds stored:
LocationNo. of seeds
(weight grams)
of plants
Collection number
Collection location
% ViabilityStorage
11350+11250 (20.43+20.25 g)
23800 (42.8 g)
Flinders Ranges
31-Mar-200685%+5°C, -18°C
BGA~2000 (4.17 g)1-Dec-2004KHB Tarcowie
Flinders Ranges
31-Mar-2006no record-18°C
BGA630 (0.6939 g)KHB037
Flinders Ranges
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.