Grass and grass-like plants include the true grasses (family Poaceae), rushes (family Juncaceae) and sedges (family Cyperaceae).

These plants all have tiny, simple flowers and are wind pollinated. They occupy a variety of habitats from low elevation wetlands to dry wind blown mountain ridges.

Within the North Cascades, true grasses include approximately 150 species half of which are native. Of the species that are non-native, the worst invader is reed canary grass (Phalaris arundinaceae). It can be found in wetlands, on lakeshores, and river edges.

Rushes and sedges are invaluable for their ability to stabilize stream banks, filter sediments, and along with many true grasses they provide habitat and food for numerous animals and other organisms.