Like grasses, sedges are annuals or perennials, nonwoody, with linear, parallel-veined leaves whose lower portions sheath the stems. The flowers are spikes: the tiny flower lacks petals and sepals but is enclosed in scales (tiny bracts). The spikes can be in arranged in spikes, racemes, panicles, or umbels.
Key features of sedges: Stems are very often triangular in cross-section and are solid, not hollow. Leaves are usually 3-ranked (they come out on 3 sides of the stem) (while true grasses are 2-ranked, opposite). Leaf sheaths are usually tightly closed or fused (in grasses, the sheaths are split open lengthwise). Flower clusters often have 1 or more leaves spreading out from the base. Fruits are 2- or 3-sided achenes (dry, single-seeded fruits that don’t split open).
Similar species: Plants in the rush family typically have basal leaves; round, solid stems; and flowers with 3 sepals and 3 sepal-like petals. Fruits are many-seeded capsules that split open lengthwise.