||P.2 right column 2nd paragraph: "The largest group of cells in the outer (abaxial) sepal epidermis of Arabidopsis appears to be a distinct class in that they bulge from the plane of the epidermis (Figure 1A–C). [Investigators] designate these as giant cells (Figure 1B–C). Giant cells average 11,000 µm^2 (±5,400 µm^2 s.d.) in area and 360 µm (±150 µm s.d.) in length (n = 62). The longest giant cells can reach 800 µm. The giant cells are interspersed between smaller cells, which are level with the plane of the epidermis. Both giant cells and small cells have a range of sizes and constitute the pavement cells, which are the primary epidermal cell type that serve to form a protective barrier for the organ. In addition the epidermis contains hair cells (trichomes, which are not present on all sepals) and guard cells, which constitute 29% (±3% s.d., n = 12 sepals) of the cells in the outer sepal epidermis. Guard cells surround the stomatal pores and regulate gas exchange [ref 39]."