Definition

Noun: 1. A taxonomic category in mycology: A former genus name for a group of imperfect fungi (fungi for which a sexual reproductive stage was not known or observed). Species once classified under Rhizoctinia are now primarily reclassified into other genera, such as Pellicularia and Corticium, after their perfect (sexual) stages were discovered.

Usage Notes

• This term is used almost exclusively in scientific, particularly mycological (fungal), contexts.
• It is a historical taxonomic name. In modern fungal classification, it is considered a form genus (a genus based on morphology rather than known genetic or reproductive relationships).
• The term is often encountered in older literature or in the context of plant pathology, as some species cause diseases like damping-off or root rot.

Examples

• Scientific Context:
  • The fungus was initially identified as belonging to the genus Rhizoctinia.
  • Several pathogenic species formerly in genus Rhizoctinia are now classified under Pellicularia.

Advanced Usage

• The term can be used to discuss the history and evolution of fungal taxonomy.
  • The reclassification of genus Rhizoctinia illustrates the impact of discovering perfect stages on fungal systematics.

Variants and Related Words

• Rhizoctonia (noun): The form of the name more commonly used to refer to the anamorph (asexual stage) of these fungi, especially in plant disease contexts (e.g., ).
• Form genus (noun): A classification category for organisms that are grouped based on similar physical form, often used when relationships are unclear, as was the case with .

Synonyms

• Form genus Rhizoctinia (This is a more precise synonym, explicitly stating its taxonomic nature.)

Different Meanings

• This term has a single, specific meaning in scientific nomenclature. It does not have general English usage or idiomatic meanings.

Noun

1. form genus of imperfect fungi some species of which are now placed in genera Pellicularia and Corticium because their perfect stages have been found