Do Orchids Have Adventitious Roots?

Monopodial Orchids

• A monopodial orchid has a single stem that grows indefinitely. Leaves grow from the end of a monopodial stem. Spikes of flowers and adventitious aerial roots grow from the sides of the stem. Monopodial orchids grow vertically.

Epiphytic Orchids

• Epiphytic or aerial orchids are monopodial. They are not parasites. The adventitious roots that grow from the stems of epiphytic orchids have a spongy layer of cells that absorb nutrients and rainwater. They also contain chloroplasts that enable them to perform photosynthesis, and they often look green when they are wet An example of a commonly grown epiphytic orchid is the Vanda that originated in Southeast Asia. The Vanda produces long, trailing adventitious roots.

Climbing Orchids

• Climbing orchids are monopodial. They often grow from the ground and climb up trees. Climbing orchids grow extensive aerial roots that are adventitious and function in the same way as the adventitious roots of epiphytic orchids. Orchid fanciers commonly grow the climbing species Vanilla pilifera that originated from tropical regions of Southeast Asia.

Sympodial Orchids

• Sympodial orchids grow laterally on the ground from spreading underground shoots called rhizomes or from bulb-like stems called pseudobulbs. However, in some species a young plant may grow adventitious roots that anchor onto the stem. An example of this is the showy orchid genus Cattleya on which a rhizome may grow from an undeveloped bud on the stem and find its way into the ground.