The brown, glabrous, 4 mm wide petioles have four primary air canals.

[2] The sterile, 8–12 cm wide flowers float on the water surface.

They are attached to reddish brown, glabrous, 6.5 mm wide peduncles with six primary central and twelve secondary peripheral air canals.

[3] The clonal species Nymphaea siamensis reproduces exclusively through the formation of bulblets on the rhizome, as well as occasional tubiferous flowers.

[1] The type specimen was collected by W.La-ongsri in Chiang Mai, Queen Sirikit Botanic Garden, Thailand on the 20th of August 2000.