lazy gardener,
Never eaten cattails, mostly because the water I frequent doesn't have them. I don't do a lot of foraging, but only eat edible weeds from my garden since I know they're not sprayed with anything and I don't have to work hard to get them. Redroot pigweed, lambsquarters, and...
Common lambsquarters are Chenopodium album. In some regions people call them pigweed, but it's sort of a misnomer. All true pigweeds are from the genus Amaranthus (wild amaranths). They look somewhat similar. Both plants are edible for humans. Just make sure to use pigweed less than a foot...