Fig. 2

Two development types in Piper in Taiwan. a–d Stem transverse sections of development stages in P. betle. a The pith surrounded by approximately 12 medullary vascular bundles (mvb), a ring of sclerenchyma (scl), and an indistinct number of cortical vascular bundles (cvb) in the outer cortex. b The mvb increase in number, approximately 19 mvb and an indistinct number of cvb. c The ring of scl begins to separate as the wide rays of secondary parenchyma are initiated, an indistinct number of cvb in the outer cortex. d Approximately 18 mvb and 38 peripheral vascular bundles (pvb), mc in the outer cortex, and showing rounded-elongate phloem (ph) and vessels of xylem (xy). e–h Stem transverse sections of development stages in P. kadsura. e Approximately 10 mvb and a ring of scl, and the cvb develop apparently. f Both mvb and cvb continue to grow, approximately 7 mvb, 20 cvb. g The scl ring appears apparently, and secondary production is limited to the cvb, approximately 11 mvb and 24 cvb. h Approximately 9 mvb and 22 pvb, all the pvb continue to grow, and become longer than the mvb in length, and showing triangular phloem (ph) and vessels of xylem (xy). Scale a, b, e to h = 1 mm; c, d = 2 mm