Fig. 7.

Details of lobed stems and stem splitting (ontogeny 4). (A–C) Urvillea uniloba. (D) Urvillea stipitata. (A) Split lobe. Note the formation of phloem wedges (top box; see detail in panel B) and rays with curved path in the periphery of the lobe (bottom box; detail in panel C). (B) Detail of phloem wedge and large rays (white arrowheads) with straight course near the phloem wedge. (C) Curved rays in the secondary xylem (yellow arrowheads) in the lateral part of the lobe. (D) Curved rays running from secondary xylem to secondary phloem (yellow arrowheads) in the lateral part of the lobe. pe, pericycle; sph, secondary phloem; sxy, secondary xylem.