exodermis

Pronunciation key ( ĕk′sō-dûr′mǐs )

ex•o•der•mis

n.

1. Botany. Temporary protective layer of cells in some roots such as in certain species of orchids.

Usborne Science Encyclopedia ©2002: "All parts of a juvenile plant are surrounded by a thin layer of tender tissue called the epidermis. In older stems, the epidermis is replaced by bark. In other roots is is replaced by a layer of hardened cells called an exodermis, then by bark. An outer tissue which encloses the plant such as the epidermis is known as dermal tissue."

References

The American College Dictionary (Random House) ©1949

Usborne Science Encyclopedia ©2002