Cyperaceae: Sedge Family — Tule, Bulrushes et al
“Reeds and rushes are round but sedges have edges”. There is some truth in this popular saying, but it is not always correct. However, it does explain why Bulrushes have triangular stems, which may be sharp-edged. This is because they are sedges (Cyperaceae), not reeds or rushes (Juncaceae).