Cyperus congestus, commonly known as dense flat-sedge or clustered flat-sedge,[1] is a sedge of the family Cyperaceae that is native to southern Africa mostly in South Africa, Lesotho and Namibia.[1]

Dense flat-sedge
Cyperus congestus inflorescence, near Glen Innes, NSW, Australia
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Cyperaceae
Genus: Cyperus
Species:
C. congestus
Binomial name
Cyperus congestus
Synonyms

Mariscus congestus (Vahl) C.B.Clarke

Cyperus congestus habit
Cyperus congestus stem, leaf and inflorescence

Description

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The perennial sedge typically grows to a height of 1 metre (3.3 ft) and has a tufted habit. It blooms between July and March produces brown flowers.[2] The sedge has a short rhizome connecting plants together. The culms are smooth and triangular in cross section, they are a pink-red toward the base. The leaves have a width of 4 to 8 millimetres (0.16 to 0.31 in) and are ridged with deep sharp depression down the middle. Between two and seven inflorescences can be found on each stem. The inflorescence are composed of up to 20 or smaller red-brown spikelets which are 10 to 28 mm (0.39 to 1.10 in) in length.[3] After flowering it will form a trigonous dark brown-black nut with a narrow-obovoid shape that is approximately 1.5 mm (0.059 in) with a diameter of around 0.6 mm (0.024 in).[4]

Taxonomy

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The species was first formally described by the botanist Martin Vahl in 1805 as part of the work Enumeratio Plantarum The name of the species is often misapplied to Cyperus polystachyos.[5] The species name congestus is Latin and means crowded and probably referring to snug way in which the fruit lies along the spikelet.[3] The only known synonym for the species is Mariscus congestus as described by C.B.Clarke.[4]

Distribution

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Its native range includes Mozambique, Zimbabwe, South Africa, Lesotho, and Namibia.[6]

It colonises easily and has been introduced into Australia, where it has now become naturalised. Recognised as a weed in Western Australia it is found in swamps and around creeks in coastal areas of the Wheatbelt, Peel, South West, Great Southern and Goldfields-Esperance regions where it grows in sandy-clay soils.[2] The species is also found in coastal areas of New South Wales, Victoria,[7] South Australia, Tasmania[4] and around parts of Brisbane in Queensland.[1] It is also a common weed found in New Zealand and Hawaii.[1]

See also

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References

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  1. ^ a b c d "Scientific Name Cyperus congestus Vahl". Weeds of Australia. Queensland Government. Retrieved 1 October 2017.
  2. ^ a b "Cyperus congestus". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
  3. ^ a b Justin Chu (2005). "Cyperus congestus". International Environmental Weed Foundation. Retrieved 1 October 2017.
  4. ^ a b c "Cyperus congestus Vahl". PlantNET. Royal Botanic Garden, Sydney. Retrieved 1 October 2017.
  5. ^ "Cyperus congestus Vahl (misapplied to Cyperus polystachyos)". Atlas of Living Australia. Global Biodiversity Information Facility. Retrieved 1 October 2017.
  6. ^ Cyperus congestus Vahl. Plants of the World Online. Retrieved 10 October 2023.
  7. ^ "Cyperus congestus Vahl Dense Flat-sedge". Flora of Victoria. Government of Victoria. Retrieved 1 October 2017.