| When water is in short supply, the dry velamen restricts water loss from the roots. |
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| While dry, the velamen may provide a barrier to water loss via transpiration from the wet, internal cells of the root. |
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| Orchid roots are covered with a special tissue called velamen occurring only in a very few non-orchid plant families. |
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| The role of the velamen is to absorb moisture from the ambient atmosphere, and, may be, to protect from cold or heat. |
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| Over watering turns the velamen brown and mushy and the roots lose their ability to absorb water. |
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| Those attached to other plants often are vinelike and have a spongy root covering called the velamen that absorbs water from the surrounding air. |
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| They provide their nutrients via photosynthesis, they have pseidobulbes used as water cistern and aerial roots in form of ribbon named velamen. |
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| In the older parts of the roots, a modified spongy epidermis, called velamen, has the function to absorb humidity. |
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| In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes. |
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