Sometimes it is hard to really know what a weed looks like from a photo. In Victoria there are certain weeds that are the highest priority to eradicate.
To make it easier to identify what these priority weeds look like, the Department of Environment and Primary Industries has begun to put some weed spotter videos on Youtube.
If want to be on the look out for what not to buy from a market stall, then it is worth being able to identify some really invasive weeds. Unfortunately some of the plants sold on stalls at markets may be weeds and recently hawkweed was discovered at a local market. It might be attractive but it is highly invasive and illegal to sell.