Figure 3

Transverse sections of stems of Yiduxylon trilobum gen. et sp. nov. from Hubei. (a) Secondary xylem with ray cells (arrow) and tracheids. HY6-3. (b-c) Inner cortex with parenchyma cells, and outer cortex with bands of sclerenchyma cells and intervening parenchyma cells. HY8-5, HY1-7. (d-f) Enlargement of Figure 2b (arrows 1–3), respectively, showing tangentially dividing leaf trace (d) and individual leaf traces in inner cortex. (g) Partial stem showing two dividing leaf traces in inner cortex (arrows), which are enlarged in (h). HY6-7. (h-j) Serial transverse sections of two leaf traces showing their gradual tangential division to produce four traces. (h) Enlargement of (g, arrows). HY6-7, HBY6-5, HBY6-3. (k) Enlargement of right leaf traces in (i). Scale bars = 0.2 mm (a, d-f, k), 0.5 mm (b, c, h-j), 1 mm (g).