Annual up to 45cm. Leaves pinnatisect (leaf divided into leaflets arranged either side of leaf mid vein), have stipules (outer leaflike appendage at base of leaf stalk). Flowers white, petals and filaments have nipple-like surface prominence (papillate); seedpods narrowly oblong to elliptic.

Latin: diffusus = loosely irregular, diffuse; referring to the branches which diverge from axis at angle of 45 to 90 degrees.