Collar

Collar [ Biology ]

Dictionary of botanic terminology - index of names


	In Biology terminology a collar describes an encircling structure or bandlike marking or junction, as around the neck of an animal, or a plant base suggestive of a collar.

Collar [ Botany ]
Synonym: Crown, Root neck


	In botany the collar or crown is the neck or line of junction between the root of a plant and its stem;

The transition point between stem and root. The area of the axis of a plant where the tissues differentiate into stem and root and merge to each other. Normally this area appears swollen or tapered, but can also be constricted and very thin, and is located near or at soil level. It may be clearly or vaguely apparent.

The collar is a vulnerable area prone to fungal diseases known as collar rot or crown rot.

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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