Sparganium confertum Y.D.Chen

Stems emersed, erect, 15-45 cm tall. Leaves 25-55 cm × 3-5 mm, lower keeled on abaxial side. Spikes with many densely arranged heads, 6-11 cm; male heads (6-)8-12, deciduous; female heads 1-3, sessile or rarely lowest one sterile, pedunculate. Female flowers: perianth segments 3-5 × ca. 1.5 mm, lobate to parted at apex; ovary elliptic, with stalk 1.5-2 mm; styles ca. 1 mm; stigmas unilateral, 1-1.5 mm. Fruit 4-5 mm. Fl. and fr. Sep-Oct.