We just learned about this one from doing some online research:

Scientific name: 
Pyrrhopappus carolinianus

Texas Dandelion, also False Dandelion, grows commonly over the eastern half of the state. Besides growing in fields and along roadsides, it often invades yards. Its lemon-yellow flower heads bloom in the mornings from March through May.

You are welcome to download individual images or the entire set for use on your Desktop and in screen saver programs such as Webshots. To download a screen-size 800x600 image of the photo on this page, right-click on the image above and Save Target As (Internet Explorer) or Save Link As (Netscape).

To download the entire set, click on this link. This file is about 2.8 megabytes and will take about 3 minutes to download via a 56K modem.