| Noun | 1. | genus Dieffenbachia - evergreen perennial herbs of tropical America with lush foliage and poisonous sap; often cultivated as houseplantsliliopsid genus, monocot genus - genus of flowering plants having a single cotyledon (embryonic leaf) in the seed Dieffenbachia sequine, dumb cane, mother-in-law plant, mother-in-law's tongue - an evergreen plant with large showy dark green leaves; contains a poison that swells the tongue and throat hence the name |