Exotic ferns, growing lushly in moist, shaded grottoes. Not! At last count, arid Texas boasted 107 species of native ferns?more than any other U.S. state. Susan Crawford Tracy of Medina, long active in growing native plants and developing a personal arboretum, has focused on protecting, preserving and enhancing the natural biodiversity of this region. She will teach how ferns grow and how to avoid their threats.