Figure 1.

Pericycle cell length in protoxylem and protophloem radii 2 to 4 mm and 6 to 8 mm from the tip. For cells in the protoxylem radius, means ± se are given for 48 cells in 11 roots (2–4 mm portion) and for 164 cells in 11 roots (6–8 mm portion). For cells in the protophloem radius, means ± se are given for 27 cells in nine roots (2–4 mm portion) and for 35 cells in seven roots (6–8 mm portion). When in the protoxylem radius (2–4 mm), a cell had recently divided or was in division, it was treated as one cell.