Hi there
The web is chock-a-block full of information on plants and their toxicity/edidablity or not...
On dandelions there is this link.

http://intra.whatuseek.com/query.go?crid=1b532fea4043b31f&query=dandelion

I have only downloaded the one entitled -"Making dandelions palatable by John Kallas, Ph.D Issue #82 "which has good iinformation


If you know what the plant looks like, you could try this link - no pictures but full of information on habitat, edible uses. location, medicinal uses etc,etc

http://www.ibiblio.org/pfaf/D_search.html

Hope this helps