Chara in general will be a bright green color and it will look like carpet on the bottom. It will have a very distinct smell. It's nickname is skunkweed. It also will become pretty stiff and feel gritty if you put it in your hand and roll it between your fingers. If you take a nut or weight and set it on the weed bed, chara will typically support the weight and you probably wont pull it in. If it is a niad it shouldn't support the weight(unless there is a lot) and it will most likely wrap around the weight and be pulled in.Also...if you pull chara out of the water it will retain its underwater form due to it's rigid(ness) meaning you will still see stems and off-shoots. Niads, underwater, will have branches and stems, but when pulled in will look like long wet hair with no apparent branches. Niad's are typically long and skinny strands that are brown to light green in color. Naid's are more likely to reach the surface than chara in more than 1-2 ft of water. Off the top of my head, I'm not familiar with bushy pondweed.
