Seeds of South Australia
Tribulus macrocarpus (Zygophyllaceae)
Winged-fruit Caltrop
List of species for Tribulus
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Seed collecting:
July to November
Herbarium regions:
North Western, Lake Eyre
NRM regions:
Alinytjara Wilurara, South Australian Arid Lands
IBRA regions
Mann-Musgrave Block (CER01)Central Ranges
 Vulnerable   (IUCN: VU D2)
Pedirka (FIN04)Finke
 Vulnerable   (IUCN: VU D2)
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 Tribulus]
Name derivation:
Tribulus from the Greek 'tribolos' meaning water-chestnut and translated into Latin as 'tribulos' which originally meant the caltrop, a 4-pointed military instrument, employed to lame advancing cavalry, and the name also applied to Tribulus terrestris. Macrocarpus from the Latin 'macros' meaning large and 'carpos' meaning fruit; referring to its large winged fruit.
Found in the far north and north-western parts in South Australia, growing on shallow rocky and gravelly soils in hills and ranges and red sandy & loamy in plains, dunes and creeks. Also found in Western Australia and  Northern Territory.
Native. Rare in South Australia. Common in the other states.
Plant description:
Prostrate or ascending hairy annual herb. Leaves alternate, with 5-7 pairs of oblong leaflets to 7 mm long. Inflorescence solitary in axils of leaves with large yellow flowers. Flowering between April and September.
Fruit type:
Very large, sparsely hairy fruit to 23 mm long and 20 mm wide, with 5 vertical wings and 2 downward pointing spines between wings.
Embryo type:
Spatulate fully developed.
Seed collecting:
Collect fruits that are hard and turning brown. Some fruits maybe split and laying on the ground. Be careful when collecting as the fruits are spiny.
Seed cleaning:
No further cleaning is required if only fruits are collected. 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 germination:
This species have physical and physiological dormancies that needs to be overcome for the seed to germinate.