Transgenic knockout plants, cml42, show abnormal trichome branching. Representative cryo scanning electron micrograph images are presented of: A, a three-branched trichome from a wild-type plant; B–D, three-, four-, and five-branched trichomes, respectively, from a cml42 knockout plant. E and F, aerial views of a typical rosette leaf from wild-type and cml42 knockout plants, respectively, where arrows indicate trichomes with more than three branches. Scale bars: A–D = 100 μm; E and F = 1 mm.