Complex sentence: The dryland forest is comprised of an open, mixed canopy that is dominated by "Sterculiaceae" and "Ulmaceae"; often associated with it is a dense understorey of "Marantaceae" and "Zingiberaceae".
Split into simpler sentences: The dryland forest is comprised of an open, mixed canopy that is dominated by "Sterculiaceae" and "Ulmaceae". Often associated with it is a dense understorey of "Marantaceae" and "Zingiberaceae".