Money may not grow on trees, but one day medicine might grow on bushes.That possibility and many others will be the focus Tuesday at Chicago’s Navy Pier, where the Illinois Biotechnology Industry Organization continues its annual Marketplace Conference."It’s a great place for networking among investors, researchers and entrepreneurs,” said Bill Gantz, chairman of Ovation Pharmaceuticals Inc. and president of the industry group.Speakers will include Dr. Jeffrey Leiden, president of the pharmaceutical products group at Abbott Laboratories; Nick Galakatos, general partner at MPM Capital; and J. Erik Fyrwald, group vice president at DuPont Agriculture and Nutrition.Among the workshops will be one that discusses plants and therapeutics, including the goal of growing medications.