Similar to Cycnogeton procerum but plants never robust; tubers smaller and plumper, 8–20(–28) mm long, 5–12 mm diam., 1–3 times as long as broad; leaves smaller and more slender, their emerged portions floating, never erect, (6–)26–91 cm long, (1–)2–8 mm wide; scape at fruiting usually shorter and more slender, c. 27–67 cm long, c. 1.5–6 mm diam.; mature fruits distinctive in shape and fewer, 1–67 per infructescence, usually somewhat broader than long, globular to depressed globular in outline, 5.6–8.7 mm long and 6.6–9.9 mm diam.; mature carpels ventrally attached along only the lower 20–39% of the carpel length (the free upper portion of the carpels may be partially spiralled around each other), each with broad-convex dorsal and lateral ridges; all (5 or)6 carpels mature or else 1 or 2 (sometimes more) abort. Fruits (Sep.–)Oct.–Dec.(–Jan.).