Organ

Organ [ Biology ]
Synonym: Bodily organ

Dictionary of botanic terminology - index of names


	A bodily organ is a natural part or structure of an organism; a distinct, fully differentiated unit consisting of a group of two or more tissues, one of which usually predominates, which function as an integrated unit and performing some specific functions

For example, the ovary is an organ that produces ovules, the root is an organ that absorb water and nutrients, a leaf is an organ that carry out the photosynthesis.
Groups of organs that perform related functions constitute a system or apparatus.

Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994