Globetrotter's Guide to Greenery: Freshwater Marshes

You're walking through the forest... There are trees... Oaks, pines... Some shrubs...Uhh... So, what's growing over there, GM? What is Globetrotter's Guide to Greenery? Have you ever found yourself in a situation where your mind just goes blank while looking for a description of the landscape? Did your players go for days through an almost-sterile jungle because you kinda forgot how's that bloody…