Here are two plants of Australia.
Senecio Madagascariensis is a fireweed. It is becoming a serious pest in New South Wales. It is also begining to spread into Queensland. It has 25,000 to 30,000 seeds per plant. And it has almost 100% germination rate.
ACACIA PARRAMATTENSIS: The Acacia Parramattensis is part of the "Black Wattle" group. It is also a weed. Many of Australia's plants are weeds.