Flower and leaves. Photo: Don Wood, Scotia Sanctuary, NSW

Flower, leaves, and burr. Australian Plant Image Index, photo: Murray Fagg, O'Connor, ACT

Young fruiting bodies and leaves. Photo: Don Wood, Scotia Sanctuary, NSW

Mature burr and leaf. Australian Plant Image Index, photo: Murray Fagg, O'Connor, ACT

Plant. Australian Plant Image Index, photo: Murray Fagg, O'Connor, ACT

Common Name

Caltrop, Cat-head

Family

Zygophyllaceae

Notes

Introduced annual or perennial forb, prostrate.  Plant hairy when young.  Leaves opposite each other, composed of 4-7 pairs of flat leaflets each 0.4-1.2cm long, 1-5mm wide, sparsely hairy above, hairy below, tips blunt or pointed.  Flowers yellow, with 5 petals, borne singly at the bases of the leaves.  Burrs usually with 10 main spines with many spines or protuberances between them, hairy or hairless.  Declared plant in SA.  Noxious weed Vic.

Differs from Tribulus eichlerianus in that the individual sections of the fruiting body are 4-8mm long and have few spines.

Description and photo in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales page 438

PlantNET description:  http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Tribulus~terrestris