I have never attached pictures so I hope this shows up. These weeds are growing all over in my garden and I don't want to pull them if my sully can eat it. Never thought I would want to keep the weeds in my garden!
Here is a good weed ID tool I found.
It won't tell you if it's safe but it might help figure out what it is.
Tip a wrong answer is worse than none. http://weedid.wisc.edu/ca/weedid.php
I'm pretty sure it's in the sunflower family, making it good for a tortoise to eat. Specifically, I think it's a baby of some kind of spineless thistle. They grow everywhere around here, and grow to be over a foot tall. My guys love them.
Here is another thread about what I believe is the same species: