Canker

Canker [ Phytopathology ]
Synonym: Anthracnose
Adjective: Cankered

Dictionary of botanic terminology - index of names

Canker (or anthracnose) is a general terms used to indicate a large number of different plants diseases that causes localized necrotic lesion to the bark, root, stem or branch.

Cankers is an imprecise term for a number of different plant diseases characterised by broadly similar symptoms: the appearance of small discoloured, often sunken areas of dead tissue arising (in woody plants) from the death of cambium tissue outside the xylem cylinder or (in non-woody plants) by the formation of sharply delineated, dry, necrotic, localized lesions on the stem.

Cankers usually grow slowly, often over a period of years, but sometimes limited in extent by host reactions which can result in more or less massive overgrowth of surrounding tissues.

Some cankers are of only minor consequence, but others are ultimately lethal, and of major economic importance in agriculture and horticulture. Canker causing organisms sometimes exist in some sort of a balance with the host, never killing enough tissue to cause death. Cankers tend to weaken plants at the points where they are growing causing the plant to eventually break.

Different cankers and anthracnoses are caused by a wide range of pathologic organisms, including fungi, bacteria, mycoplasmas and viruses.

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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