Update--breeding grebes at Lake Henry

Yesterday I stopped by Lake Henry to check on the Clark's and Western Grebes that have been breeding there. I found several parent's with dependent juveniles like this Clark's Grebe swimming behind it's parent. There were also some grebes still nesting in the floating vegetation that formed a mat on the lake (visible in this pic). If anyone can identify the floating vegetation, shown in this pic (click on the pic to enlarge it for a close-up of the vegetation), I would appreciate your noting what it is--just click on the "comment" link at the bottom of the post. SeEtta