Close-up views:

Praxelis is native to South America [1-3]. It is not listed in the Singapore Flora checklist published in 2009. Due to the close similarity in its general appearance with the White Weed (Ageratum conyzoides), another common weed in Singapore, it real identity may have been masked for many years. In Australia where it was first recorded in 1993 and naturalised, a report published in 2003 indicated that it was probably present there for at least 10 years before being positively identified [1]. Besides Australia, it is also naturalised in China [4].

Also, it may have been confused with another weed, Adenostemma viscosum which is listed in the Singapore Flora checklist.

Reference:

[1] Waterhouse BM. Know your enemy: recent records of potentially serious weeds in northern Australia, Papua New Guinea and Papua (Indonesia). Telopea 2003;10(1):477-485. | Abstract |

[2] Gardner AG, Williges KA. Praxelis clematidea (Asteraceae): A New Plant Invader of Florida. Southeastern Naturalist 2015;14(1):N21-N27. | Abstract |

[3] Falcao Hde S, Maia GL, Bonamin F, Kushima H, Moraes TM, Hiruma Lima CA, Takayama C, Ferreira AL, Souza Brito AR, Agra Mde F, Barbosa Filho JM, Batista LM. Gastroprotective mechanisms of the chloroform and ethyl acetate phases of Praxelis clematidea (Griseb.) R.M.King & H.Robinson (Asteraceae). J Nat Med 2013;67(3):480-91. | Abstract |

[4] Wang Q, Huang M, Downie SR, Chen Z, Chen Y. Genetic diversity and structure of the noxious alien grass Praxelis clematidea in southern China. Biochem Syst Ecology 2015;59:183-189. | Abstract |

Online Resources: | Weeds of Australia |