Siratro (species: Macroptilium atropurpureum) in taxonomy (Lizard Island Field Guide)
Macroptilium atropurpureum

©Cassy Thompson: Siratro at Lizard Island showing trifoliate leaf, purple pea-flower and seed pods.

©Anne Hoggett: Macroptilium atropurpureum at base of gully on SW side of Cook's Look, Lizard Island.
Kingdom Plantae
Division Tracheophyta
Class Magnoliopsida
Order Fabales
Family Fabaceae
Genus Macroptilium
Species Macroptilium atropurpureum



Distinguishing features

A creeping and climbing legume with broad trifoliate leaves 2-7 cm long with spiky hairs on the underside. Dark purple pea flowers develop into long narrow seed pods.


  • Size data has not been obtained.



This plant is native to tropical America and is used in Australia as a pasture plant. It is an environmental weed that smothers native plants. It pops up occasionally on the LIRS lease where it is controlled by hand removal or by spraying with the herbicide Brushoff as advised by QPWS (1 g granules dissolved in 10 litres freshwater). 

by Anne Hoggett


©Atlas of Living Australia: Australian distribution

Local abundance

  • Lizard Island: This weed has been at Lizard Island since at least the early 1990s.

Local feral populations

  • Lizard Island:  Regarded as a serious weed - introduced and invasive

Web resources


  • Colvill, A., M. Ahmet, S. Clag and B. Haigh (2004). Lizard Island fauna and flora sampling report.Queensland Parks and Wildlife Service. LIRS catalog number 10067.
  • De Sloover, J.R. and A.-L. Jacquemart (2008). Nymph Island (Great Barrier Reef, Qld., Australia): Flora and vegetation of a low wooded island, Scripta Botanica Belgica, 43: 1-88. LIRS catalog number 1210.