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.