By Donna Cornelius From furniture built long ago to designers whose aesthetics are shaping modern sensibilities, Antiques at the Gardens is a showcase for timeless beauty. The 16th annual event, hosted by the Friends of the Birmingham Botanical Gardens, kicks off Sept. 29 and runs through Oct. 2. It includes 12 speakers, 22 dealers and about 150 volunteers – all working together to support the Gardens and to educate and entertain those who attend. First Horizon Bank is the presenting sponsor of this year’s show, which features textile sponsor Sister Parish Design as well as talks and book signings by nationally and internationally acclaimed interior designers, floral designers, architects, landscape architects and furniture designers.  Dealers will…