It has a slender, fibrous, knobbly or gnarled, brown-black rhizome. It has short, thick rhizomes, which are gnarled and knobbly. The holdfast is a large, bulbous hollow, knobbly structure. It has a knobbly, ridged back and three large bony tubercles on each flank. It had a flat turtle-like carapace covered with knobbly plates, and a compact triangular skull. It has knobbly, woody, tough, short and thick rhizomes. It has knobbly, woody, rhizomes. The humpback has a distinctive body shape, with long pectoral fins and a knobbly head. "Arandaspis" was about long, with a streamlined body covered in rows of knobbly armoured scutes. It has a slender, knobbly, dark rhizome. "Iris cathayensis" has a brown, tough, knobbly rhizome. "Iris qinghainica" has a knobbly rhizome. The drawing consisted of Dennis's trademark messy hair cut, knobbly knees and menacing scowl. The 'Irish Lumper' has been characterized as a "wet, nasty, knobbly old potato". The shell edges are knobbly and crossed.