Wrapper -Tucker patterning in grass leaf margins. A) Grass shoots exhibit a non-random, patterned arrangement of Wrapper/Tucker (W/T) the leaf margins. In the sample shown, all sheath margins arising from the left half of the stem axis are Wrappers, whereas sheath margins arising from the right side of the axis are Tuckers. (B) ZmCUC2 transcripts, markers of boundary formation, localize asymmetrically and predominately in the Tucker margin. (C) Non-random patterning in wild type plants. (D) An aberrant, random pattern of Wrapper/Tucker margins is seen in higher-order wox3 mutants, although they have wide leaves. The leaf terms “Wrapper and Tucker” were coined by E. Coen.