Tyrtle said:I believe that is called Hoary Cress. Check out the link here:
http://www.colorado.gov/cs/Satellite?c=Page&cid=1167928184099&pagename=Agriculture-Main/CDAGLayout
Tortoise table lists it as "feed in moderation".
http://www.thetortoisetable.org.uk/site/plants_19.asp?catID=563