haustorium

Specialized organ produced by a parasitic plant or fungus that penetrates the cells of its host to absorb nutrients. It may be either an outgrowth of hyphae (see hypha), as in the case of parasitic fungi, or of the stems of flowering parasitic plants, as in dodders (Cuscuta). The suckerlike haustoria of a dodder penetrate the vascular tissue of the host plant without killing the cells.