Purple flower/weed poisonous for guinea pigs?

[wheekmau5]

There are a lot of these patches of purple flowers/weeds in my backyard so I did not put my guinea pigs out on the run. Do you think they are poisonous to guinea pigs ? I will try try to take a picture with my phone ( low-quality )

[lissie]

Do you know the name of the weeds? Here's a poisonous plant list (scroll down towards the bottom).
http://www.guineapigcages.com/forum/...ants-list.html

[wheekmau5]

I have no idea on what they are called, I will take a pic and send to a botanist forum.