Definition

Proper noun * Family Nostocaceae: A taxonomic family of cyanobacteria (blue-green algae) characterized by forming colonies of cells within a gelatinous sheath. Members of this family are found in diverse aquatic and terrestrial habitats and can fix atmospheric nitrogen.

Usage

• Scientific Classification: Used primarily in biological and microbiological contexts to classify a specific group of cyanobacteria.
  • The sample was identified as belonging to the family Nostocaceae based on its filamentous structure and heterocyst formation.
  • Researchers are studying nitrogen fixation in several genera within the family Nostocaceae.

Advanced Usage

• Taxonomic Hierarchy: The term is used within a specific rank in biological classification: Domain (Bacteria) > Phylum (Cyanobacteria) > Class > Order (Nostocales) > Family (Nostocaceae) > Genus (e.g., , ) > Species.

Variants and Related Words

• Nostocaceae: The standard form, often used without "family" in technical writing.
  • The order Nostocales includes the families Nostocaceae and Rivulariaceae.
• Nostocacean (adjective): Of or pertaining to the family Nostocaceae.
  • The nostocacean cyanobacteria formed visible mats on the pond surface.

Synonyms

• Blue-green algae (family): A common, informal name for the broader group, though not a precise taxonomic synonym.
• Cyanobacteria (family): The more precise modern term for the bacterial phylum, specifying the family level.

Notes on Meaning

• The term refers exclusively to a formal taxonomic grouping in scientific nomenclature. It is not used in everyday language.
• While "blue-green algae" is a historical and common name for these organisms, it is important to note that they are bacteria (prokaryotes), not true algae (eukaryotes). The family Nostocaceae is a subset of all cyanobacteria.

Noun

1. blue-green algae