Aster Family flowers usually look something like a sunflower, that is, they usually have a central disk surrounded by "petals" (strictly speaking, the latter are 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 genus and species. Click on a link or photo to reach a page with additional photos of a species, plus comments. That page is bandwidth-intensive and best used with a high speed connection.
Please don't take my IDs as authoritative. These pages of nature photos represent one person's voyage of discovery, not the studies of a trained expert. If you see something I've misidentified, please contact me via my "Contact" page, which is tabbed at the top.