Mark Reynolds
Well-known member
Sedges have edges, rushes are round, Grasses have nodes all the way to the ground. Nodes are the conspicuous raised places on a grass stem that give rise to the leaves; the structures are much less obvious in sedges and rushes. "Grassologist" terminology.I was always told to cut the stem...if the cross-section is triangular, it is a sedge. If round, it is a grass. But I'm no grassologist.

(Some grasses are actually flat. take a look at a 'sprig' of orchard grass some time and note how the leaf sheaths are folded and make up a flat stem at the base.)