This species can be recognized by its robust habit, leaves that are pubescent below but with the pubescence transparent or gray (not bright white), many-flowered inflorescences with the axes becoming markedly scorpioid, and its showy white to yellow, pink, or purple corollas that have 6 lobes and are densely bearded in the throat.
This species is not commonly collected and apparently local, and has sometimes been overlooked. It is very similar to Isertia haenkeana, which is more widespread and more commonly collected. However I. haenkeana differs in its red to yellow flowers and its drupaceous fruits with 5-6 locules, vs. berry fruits with 2-3 locules in I. scorpioides. These also differ in their inflorescence arrangement, but this distinction can be difficult to see in plants just beginning to flower: I. haenkeana has the inflorescence axes mostly dichasial, while the axes of I. scorpoioides are initially dichasial but as they develop, they become markedly scorpioid, and apparently unbranched and linear.