The term 'yellow-flowered weed' can refer to two different plants: the DANDELION (9 letters) and the tansy (5 letters). The DANDELION is a flowering plant in the family Asteraceae, native to Eurasia and North America. It has a bright yellow flower head and is considered a weed due to its ability to spread quickly. The tansy is a flowering plant in the family Asteraceae, native to temperate regions of Europe and Asia. It has a bright yellow flower head and is also considered a weed due to its ability to spread quickly.