Here's a nice link for lot of info on wild onions. http://www.wildfoodforagers.org/wgonion1.htm
That said, the picture of the lone wild onion at the top of the first page doesn't look like MY wild onions. The one they have pictured has flat leaves, mine have round leaves. The site seems to be from Louisiana, so that might account for the difference. Let's face it - you know it's an onion or not once you break a leaf and smell the distinctive onion fragrence!