Fig. 7. Abnormal vasculature in sem1 mutant leaves. (A) Ectopic proliferation of margin tissue at the blade-sheath boundary of a mutant leaf shows extensive transverse vasculature elements. b, blade; s, sheath; l, ligule. (B-G) Cleared and stained sheath tissue of (B-D) non-mutant and (E-G) sem1 mutant leaves. (B,E) Just proximal to the ligule and midway between the midrib and margin. (C,F) As in B and E, but 4 cm proximal to the ligule. (D,G) Near the margin, 4 cm proximal to the ligule. The sem1 mutant sheath shows poor development of transverse veins. Scale bar in B: 50 µm for B-G.