Definition of velamen in English:
noun (plural velamina /-mɪnə/)Botany
An outer layer of empty cells in the aerial roots of epiphytic orchids and aroids.
- Over watering turns the velamen brown and mushy and the roots lose their ability to absorb water.
- When water is in short supply, the dry velamen restricts water loss from the roots.
- The role of the velamen is to absorb moisture from the ambient atmosphere, and, may be, to protect from cold or heat.
late 19th century: from Latin, from velare 'to cover'.