Seeds of South Australia
Thomasia petalocalyx (Sterculiaceae)
Paper-flower
List of species for Thomasia
Display more images
Click on an image to enlarge it
Seed collecting:
November to February
Herbarium regions:
Eyre Peninsula, Northern Lofty, Murray, Yorke Peninsula, Southern Lofty, Kangaroo Island, South Eastern
NRM regions:
Adelaide and Mount Lofty Ranges, Eyre Peninsula, Kangaroo Island, Northern and Yorke, South Australian Murray-Darling Basin, South East
IBRA regions
Bridgewater (NCP01)Naracoorte Coastal Plain
 Least Concern
Lucindale (NCP03) 
 Least Concern
Tintinara (NCP04) 
 Least Concern
Kangaroo Island (KAN01)Kanmantoo
 Least Concern
Fleurieu (KAN02) 
 Least Concern
Mount Lofty Ranges (FLB01)Flinders Lofty Block
 Near Threatened
Southern Yorke (EYB01)Eyre Yorke Block
 Rare   (IUCN: RA d(ii))   (Probable Decline)   [no old herbarium records, mostly HAs, roadsides]
Eyre Hills (EYB03) 
 Endangered   (IUCN: EN D)
Murray Mallee (MDD02)Murray Darling Depression
 Near Threatened
Murray Lakes and Coorong (MDD03) 
 Least Concern
Lowan Mallee (MDD04) 
 Least Concern
Wimmera (MDD05) 
 Data Deficient   [imprecise location]
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 Thomasia]
Name derivation:
Thomasia named after Peter and Abraham Thomas, 18th century Swiss brothers, who were botanists and plant collectors. Petalocalyx from the Greek 'petalum' meaning petal and 'calyx' meaning covering; referring to the petal-like sepals.
Distribution:
Found in the southern part of South Australia, growing on poor sandy soils and limestone in mallee and coastal woodlands. Also found in Western Australia and Victoria.
Status:
Native. Common in South Australia. Common in the other states.
Plant description:
Perennial shrub usually less than 1 m high with hairy branches. Leaves to 4 cm long and 10 mm wide, oblong, obtuse both ends or subcordate at base, irregular curving of the margins, densely stellate-tomentose to glabrescent above, stellate hairs on veins bellow. Inflorescence a 5 flowered raceme with lax flowers, calyx mauve to 10 mm long. Flowering between August and November.
Fruit type:
Brown papery, ovoid capsule to 9 cm long, with 3 cells.
Seed type:
dark brown to black ovoid seed to 3 mm long and 1.5 mm wide, with a cream aril.
Embryo type:
Spatulate fully developed.
Seed collecting:
Collect fruits that are turning brown and starting to dry. Rub the fruits in your palm to seed if there is any seed, which should be brown and hard.
Seed cleaning:
Place fruits in a tray and leave to dry for a week. Then rub the heads with your hands or 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.
Seed viability:
From one collection, the seed viability was low, at 16%.
Seed germination:
This species has physiological dormancy that need to be overcome for the seed to germinate (e.g. nicking or softening the seed coat).
Germination table:
DateResultT0T50Pre-treatment | Germination medium | Incubator: Photoperiod / Thermoperiod
Nov-1494%17 d17 d seed coat nicked with scalpel;
1% agar;
Incubated under winter conditions
Jul-1488%21 d28 d seed coat nicked with scalpel;
1% agar;
Incubated under winter conditions
Jul-1460%21 d52 d seed coat nicked with scalpel;
1% agar;
Incubated under spring/autumn conditions
Jun-154%58 dNA
1% agar;
Incubated under spring/autumn conditions
Jun-150%NANA
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)