Aster Family flowers usually look something like a sunflower, that is, they usually have an obvious central disk surrounded by rays. There are exceptions. For yellow to orange flowers that aren't in the Aster Family, click here.
Flowers are shown in alphabetical order by English family name, genus, and species. Click on a link to reach the family page and find additional photos of a species, plus comments. That pages is bandwidth-intensive and best used with a high speed connection.