Soft plants, much-branched, with watery stems. Flowers orange with red or reddish-brown spots; shaped like a cornucopia; with 3 unequal sepals, 2 of them small, the third a sack with a spur; 5 petals, appearing as 3 (as the laterals are joined), each with 2 lobes; stamens joined to the stigma; each flower hanging from a slender stem. The conical portion of the flower is usually about twice as long as it is wide. Blooms June–September. Leaves alternate, soft, egg-shaped, bluish-green, coarsely toothed, to 3½ inches long. Fruit a slender capsule which, upon drying or when touched, contracts, coils and splits explosively, casting seeds far away in all directions.
Similar species: Pale touch-me-not (I. pallida) has lemon yellow flowers, and the conical portion of the flower is about as long as it is wide, with a shorter spur. Without seeing the flowers, it is almost impossible to distinguish between the two species.