In situ hybridization of Class I KNOX genes and MsH4 in shoot apices of terrestrial (Tf) and climbing (Cf) forms of Mickelia scandens. (a) Longitudinal section of Tf. Expression of MsC1KNOX1 in the shoot apical cell (arrowhead), leaf apical cell (*), derivative cells, and procambial strands (ps). (b) Cf, longitudinal section. MsC1KNOX1 expression in a peripheral zone and procambium. Leaf primordia position pointed out by arrowheads. (c) Longitudinal section of Tf. MsC1KNOX2 expression in the shoot apical cell (arrowhead), derivative cells, and procambial strands (ps). (d) Longitudinal section of Cf. In this apex, MsC1KNOX2 expression is not detected in the shoot apical cell. There are procambial strands (arrowheads) connecting the SAM and the leaf primordia. (e) Transverse section of Tf. MsC1KNOX2 expression in a large apical cell (arrowhead) and in the surrounding derivative cells. (f) Longitudinal section of Cf. Scattered MsH4 expression in the SAM (white arrowhead) and in the developing vascular system (black arrowheads). Bars: (a) 100, (b) 200, (c) 75, (d) 200, (e) 50, (f) 125 µm.