EPFL1, EPFL2, EPFL4, and EPFL6 redundantly regulate the size of the SAM and the rate of leaf initiation. Comparison of the SAM width (A) and the number of formed leaf primordia (B) in the wild type, er erl1 erl2, and epfl family mutants determined by DIC microscopy at 3 DPG (solid bars) and 5 DPG (dotted bars). Bars represent the average; error bars represent sd. n = 10 to 11. Values significantly different from the wild type are indicated by asterisks (based on Student t test; P < 0.006). C, DIC images of meristematic regions in the wild type, er erl1 erl2, and epfl1,2,4,6 at 3 DPG. The meristem width is displayed with an arrow. All images are under the same magnification in (C). wt, wild type.