What is the difference between these terms: bulb, corm, rhizome and tuber? We all use these terms, but what do they mean? How do you tell the difference between them?
Bulb: an upright, underground stem with overlapping, fleshy sales (think onion, tulip).
Corm: Underground stem with no overlapping scales OR very few scales (think crocus, gladiolus)
Rhizome: a scaly underground stem (think bearded iris or canna)
Tuber: modified underground stem produced at the tip of a rhizome (think white or sweet potato).