witches' broom
Học thuậtThân thiện
Definition
Noun: - An abnormal tufted growth of small branches on a tree or shrub: A dense, bushy cluster of deformed twigs and small branches, resembling a broom, that grows from a single point on a plant. This growth is caused by a disease, often due to infection by fungi, viruses, or phytoplasmas, or by infestation from insects or mites. It can also result from other physiological disturbances or genetic mutations.
Usage
- The term is used specifically in botany, horticulture, and forestry to describe a specific symptom of plant disease or stress.
- It is a compound noun, typically written with an apostrophe as or as a closed compound .
- Example: "The forester identified the dense, tangled mass in the pine tree as a witches' broom, a sign of possible fungal infection."
Examples
- "The apple tree's productivity declined after several witches' brooms appeared in its canopy."
- "Gardeners often prune out witches' brooms to prevent the spread of disease and to improve the plant's appearance."
- "In some plant species, a stable witches' broom mutation is deliberately propagated to create dwarf ornamental cultivars."
Advanced Usage
- The phenomenon is named for its resemblance to a broom, with folklore sometimes attributing its cause to witches.
- In plant pathology, the presence of a witches' broom is a key diagnostic symptom for specific diseases, such as those caused by the fungus on birch trees or certain phytoplasma infections.
Variants and Related Words
- Witch's broom: A common variant spelling, treating "witch" as singular possessive.
- Hexenbesen: The German term for the same phenomenon, literally meaning "witches' broom."
- Broom (in this context): Can be used informally as a shortened form, e.g., "The fir has a bad broom."
Synonyms
- Broom (botanical context)
- Tufted growth
- Dense shoot proliferation
Related Phrases
- Witches' broom disease: The broader condition or pathogen responsible for causing the abnormal growth.
- Example: "The cocoa plantation was devastated by an outbreak of witches' broom disease."
Notes
- Not to be confused with a regular, healthy dense growth of branches. A witches' broom is distinctly abnormal, often stunted, and densely packed with small, short twigs.
- While often detrimental, some horticultural varieties (like certain dwarf conifers) originated as witches' broom mutations and are intentionally cultivated.
Noun
- an abnormal tufted growth of small branches on a tree or shrub caused by fungi or insects or other physiological disturbance