Tuber--underground stem enlarged for storage of food--has nodes (unlike tuberous root)

---

Rhizome--underground stem, often has buds which sprout to form new shoots

---

Stolon--aboveground stem, has buds which sprout to form new shoots

 

---

Bulb--underground stem with fleshy leaves which store food, e.g. onion

---

Corm--fleshy underground stem with papery leaves, e.g. Gladiolus