Definition

1. Noun:
   • A species of aquatic plant: "great duckweed" refers to a specific, widely distributed type of small, free-floating aquatic plant (a duckweed) known scientifically as Spirodela polyrhiza or sometimes Lemna polyrhiza. It is characterized by having several roots on each frond (leaf-like structure).

Usage Examples

• Noun:
  • The pond's surface was covered with a dense mat of great duckweed.
  • Biologists study great duckweed for its rapid growth and potential uses in wastewater treatment.

Advanced Usage

• Scientific context: In botanical or ecological writing, "great duckweed" is used to specify this particular species within the duckweed family (Lemnaceae), often in contrast to common duckweed ().
  • The experiment compared the nutrient uptake rates of great duckweed and common duckweed.

Variants and Related Words

• Duckweed (n): The common name for the family of small, floating aquatic plants.
• Spirodela polyrhiza (n): The primary scientific name for great duckweed.
• Lemna polyrhiza (n): A former scientific name for the same species.

Synonyms

• Greater duckweed: An alternative common name.
• Rooted duckweed: A descriptive name referring to its multiple roots per frond.

Notes on Meaning

The definition "cosmopolitan except South America and New Zealand and some oceanic islands" describes the plant's geographical distribution. It means this species is found in many parts of the world (cosmopolitan) but is naturally absent from the listed regions.

Noun

1. cosmopolitan except South America and New Zealand and some oceanic islands