Banana

Not a tree — the world's biggest herb

A banana 'tree' isn't a tree — it's a giant herb! Its 'trunk' is made of rolled-up leaves. A banana is a berry with no seeds, so it's grown from shoots. Every yellow banana in the world is a twin — a copy of one plant! A banana plant fruits once and dies, and a new one grows from the root.

The banana (Musa) comes from South-East Asia and was domesticated 7,000 years ago in New Guinea; wild bananas have hard seeds, while cultivated varieties are seedless (parthenocarpy) and reproduce vegetatively. It has no trunk — a 'pseudostem' of leaf sheaths up to 9 m; the largest herb in the world. The fruit is botanically a berry. 120 million tonnes a year; 95% of exports are the 'Cavendish' variety, a genetically identical clone, so the Panama disease fungus TR4 threatens the whole industry — the 'Gros Michel' variety was lost the same way in the 1950s. Rich in potassium and vitamin B6; bananas are radioactive (potassium-40) — but safe. In the tropics the leaves serve as 'natural plates'. India is the biggest grower, Ecuador the biggest exporter.

Fun facts

• A banana is a berry, but a strawberry isn't! That's what botanists say.
• Every yellow banana in the world is a clone of one plant — twins.
• Bananas are slightly radioactive (potassium) — dangerous only if you eat 10 million.