Eleocharis (sect. Eleocharis) ser. Melanocarpae
Rhodora 31: 129. 1929.
Plants perennial, often stoloniferous, with some culms often arching or decumbent and with tips rooting. Rhizomes caudexlike, ascending, concealed by crowded culms, short, (2–) 3–4 mm thick, internodes crowded. Culms compressed, 0.5–1.3 mm wide. Leaves: distal leaf-sheaths persistent, thickly papery, apex subtruncate, tooth always present, to 2 mm. Spikelets terete, basal spikelets absent. Floral scales papery or membranous; styles 3-fid. Achenes dark-brown to often black, seldom yellowbrown, usually widest at apex, trigonous, smooth at 30X. Tubercles distinct from achene apex in color, texture, and form.