Differences Between Corm and Bulb

An Overview

Corm and bulb are the underground stem modifications, which have been modified for the storage of food and to survive under unfavourable conditions.

What is corm?

Corms are enlarged underground stems that store food for the plant during dormancy. It is spherical in shape with a flattened base and grows vertically below the ground. They are very similar to bulbs. Unlike bulbs, corms are solid and do not have scales or fleshy leaves. As the plant grows, it uses up the stored food. Crocosmia, freesia, and gladiolus are some examples of corms.

Read more: Morphology of Leaves

What is a bulb?

A bulb is an underground stem with fleshy and scale-like layers surrounding a centre bud. The base of the bulb consists of a cluster of adventitious roots. The shoots of the bulbs are developed from the lateral buds and their leaves are capable of storing food. The centre of the bulb contains an apical bud that produces leaves and flowers. Onion and garlic are the best examples of a bulb.

Also Refer: Root system

Let’s learn about the differences between Corm and Bulb.

Corm and Bulb- Differences

Morphological Features
Bulbs are structurally short stems with fleshy leaves or leaf bases. Corms are rounded, underground storage organs consisting of a swollen stem base covered with scale leaves.
Bulbs are modified leaves that store nutrients. Corms are swollen stem bases.
Bulbs comprise scales, which are the modified leaves. Corms comprise smooth modified stems.
A bulb is roughly spherical or pyriform in outline. It may be spherical, elongated or vertically compressed.
The bulb is a condensed underground shoot. The corm is an underground stem.
The buds of a bulb are borne internally. The buds of a corm are borne externally.
Clear-cut nodes are absent. A corm bears distinct circular nodes.
Corky covering is absent. The corm is surrounded by cork.
A tunic is absent. A tunic is present.
Food storage
Food is stored in the leaf bases. Food is stored in the stem.
New bulbs replace the old bulb which gets decayed. New corms arise on the sides or above the old corm.
Daffodils, hyacinths, allium, onion, and tulips are examples of bulbs. Gladiolus, freesia, and crocus are examples of corms.

Also Refer: Difference between Rhizome and Tuber

This concludes some of the basic differences between corm and bulb. Stay tuned with BYJU’S Biology for more differences and other Biology related topics.

Frequently Asked Questions on Differences Between Corm and Bulb


What is an example of a bulb?

Onion and garlic are the best examples of a bulb.


Is a potato a corm?

No. Potato is a tuber. It is an underground modification of the stem.


Is an onion a bulb or a corm?

The onion is an example of a bulb. Food is stored in the leaf bases.


Is turmeric a corm?

No. Turmeric is a rhizome which is an underground modification of stem.


Is a carrot a corm?

No. Carrot is a modification of root, whereas corm is underground stem modification. Carrot is a taproot modification of coniform type.

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