MYB-type transcription factor involved in epidermal cell fate specification. Acts as a negative regulator of trichome development, including endoreplication, by mediating lateral inhibition. Promotes the formation of hair developing cells in H position in root epidermis, probably by inhibiting non-hair cell formation. May have pleiotropic effects on flowering development and epidermal cell size through the regulation of endoreduplication. Expressed in leaf epidermal cells, stomate guard cells in leaves, cotyledons and hypocotyls, inflorescences, developing seeds and siliques. Increased number or trichomes and reduced number of root hairs. Overexpression of ETC3 results in the suppression of trichomes and overproduction of root hairs, as observed for CPC, TRY, ETC1 and ETC2.