Hi, Thanks for your question.

The biggest feature, for which it is named, is that areoles can be higher than the pad when it is new. They can rise up and give a pad a bumpy look. As they age, the pads become smooth.
Plants are smallish, generally not more than 25(30) inches, often lower.
Plants can be a bit upright—they don’t form a tree but 2-3 pads may rise up above the ground.
Spines are whitish (or very pale yellow) on new growth. Bases may darken. Spines may/may not darken over time to dirty gray or light brown. Spines often diverge in all directions and longer ones may be flattened (may not). Often 2-3(4) on new pads, later increasing to 4(6) on older pads. Some may be up to 2.5 inches long, most are shorter.
Stamens and anthers are yellow. Stigma is green.
The cladodes are obovate, but broadly rounded above (not narrow pads).
Fruit may have spines up to half an inch long, but these fall away as the fruit ages.

Joe