Dimorphism

(1) Dimorphism [ Biology ]
Adjective: Dimorphic or Dimorphous

Dictionary of botanic terminology - index of names


	In biology dimorphism means the existence of two different genetically determined forms of individual within a single biological species.

For examples: the sexual dimorphism (male and female), or some other trait independent of sex differences like distinct young and mature forms) The presence of more than two distinct forms within the same species is called polymorphism.

(2) Dimorphism [ Botany ]


	In botany dimorphism means the presence of two distinct forms of the same organ or part in a plant,

For example: spiny and spineless areoles produced from the same tubercle in Astrophytum caput-medusae

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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