Fig. 3

Lioxylon sp. a Transverse section, showing the centripetal (cp) and centrifugal (cf) xylem cylinders; scale bar = 0.5 mm; b Transverse section, showing the polygonal pith cells (arrows) between centrifugal (cf) xylem strands; scale bar = 1.0 mm; c Enlargement of b, showing details of the pith cells; scale bar = 0.5 mm; d Transverse section of the pith, showing a medullary bundle; scale bar = 0.5 mm; e Transverse section of the pith, showing scattered transfusion cells; scale bar = 1.0 mm; f Enlargement of e, showing details of the transfusion cells with large and small simple pits; scale bar = 100 μm