Perennial forb to 40cm tall, aquatic or in mud. Stems sparsely to densely warty with irregular golden warts. Leaves in whorls of 4-6. Emergent leaves 1-4.5cm long, about 3mm wide, linear, sometimes warty at the base, edges toothed, with pointed tips. Submerged leaves 2.5-10cm long, flat, dissected, with 13-23 narrow lobes. Male and female flowers on the same plant. Male flowers with 4 white hooded petals. Female flowers small (less than 3mm across), mauve to deep reddish purple, with 0 petals. Flowers in groups of 1-3 at the bases of the leaves. Rare SA.
PlantNET description with photo of dried plant: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Myriophyllum~papillosum