Fig. 4

Combination of three cambial variants or single cambial variant of stem cross section. A Successive cambia combined with axial vascular elements in segments and irregular conformation: Tetrastigma formosanum. B Axial vascular elements in segments combined with successive cambia: Anredera cordifolia. C External secondary vascular cylinders (empty star) combined with axial vascular elements in segments and successive cambia: Momordica charantia var. abbreviata. D Fissured stem/dispersed xylem combined: Dinetia hedyotidea. E Furrowed xylem of cambium continuity: Passiflora edulis. F Irregular in conformation combined with axial vascular elements in segments and successive cambia: Cayratia corniculata. PI, pith, PIC, pith cavity, RA, ray, PW, phloem wedges, 1st XY, first xylem, 2nd XY, second xylem, 3rd XY, third xylem, 1st PH, first phloem, 2nd PH, second phloem, 3rd PH, third phloem, 2nd VA, second vascular bundle, IC, irregular conformation, PA, parenchyma proliferation, DX, fissured stem/dispersed xylem