Juncaceae

Round, often pith-filled cylindrical stems and narrow grass-like or cylindrical leaves on wetland herbs; small, greenish-brown, six-parted flowers with a papery texture cluster into a loose or dense head, distinguishing rushes from the flat-leaved sedges and grasses they grow alongside.

A simple field mnemonic separates three similar wetland families by stem cross-section: sedges have edges, grasses have joints, and rushes are round.

To check whether a plant belongs to Juncaceae, compare the leaf arrangement, leaf type, flower symmetry, fruit type, and one distinctive marker together. A single feature can mislead; the family pattern is the combination.