***Dioscorea bulbifera<http://florida.plantatlas.usf.edu/Plant.aspx/…> * and ****** <http://florida.plantatlas.usf.edu/Plant.aspx/…>*Dioscorea alata <http://florida.plantatlas.usf.edu/Plant.aspx/…>* can be quite problem as a invasive here in Florida in kudzu like proportions as far as covering vegetation and smothering trees with there growth. They can make it north of here but I doubt out of zone 7. Both produce aerial tubers though D. bulbifera is spherical and smooth up to at least as large as a softball while D. alata fingerish like elogated aerial tubers with specialized claw-like hook shaped roots that will catch well in hair or fur. ***Dioscorea polystachya* is another name of which D. batatas is listed as a synonym which is an invasive problem further north but also occurs in Florida. D.bulbifera and **Dioscorea polystachya are both edible ONCE prepared properly. I grow the native D. floridana and D. villosa for the great leaf texture though though the seed pods of D. floridana are ornamental as well. Neither of those species produce aerial tubers. -- Alani