Habit and leaf form . Lamina margins crenate to serrate. Leaf anatomy . The mesophyll containing calcium oxalate crystals. The mesophyll crystals druses, or solitary-prismatic.
Minor leaf veins without phloem transfer cells.
Stem anatomy . Internal phloem absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow. Wood parenchyma apotracheal.