Cyperaceae
Cyperus

Cyperus tenax Boeckeler

First published in Linnaea 35: 504 (1868)
This species is accepted
The native range of this species is Tropical & S. Africa. It is a perennial or rhizomatous geophyte and grows primarily in the seasonally dry tropical biome.

Descriptions

Cyperaceae, K Hoenselaar, B. Verdcourt & H. Beentje. Hypolytrum, D Simpson. Fuirena, M Muasya. Flora of Tropical East Africa. 2010

Type
Type: South Africa, Cape, Zeyher 13 (B, holo.)
Morphology General Habit
Perennial, densely tufted, up to 73 cm tall, with an erect rhizome covered by old leaf bases.
Morphology Culms
Culms tufted, 5–68 cm long, 0.6–1.8 mm wide, rounded, glabrous
Morphology Leaves
Leaf sheath straw-coloured to purple, 1.5–7 cm long. Leaves up to 33 cm long. Leaf blade linear, flat or folded, 5–30 cm long, 1.1–4 mm wide, scabrid on margins and primary vein at least on young leaves, apex acuminate
Morphology Reproductive morphology Inflorescences Bracts
Involucral bracts leaf-like, spreading, the lowermost (1–)3–14 cm long, 1.2–2 mm wide
Morphology Reproductive morphology Inflorescences
Inflorescence a simple to compound anthela, primary branches 3–12, 0.5–5 cm long.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets in digitate, sessile and at the end of primary and sometimes secondary branches, 5–14 per cluster, linear, 3–19.1 mm long, 0.7–1.3 mm wide, up to 2.5 mm wide with glumes spreading, rachilla straight.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes falling off with nutlet Glumes pale reddish-brown to almost black, ovate, 1.2–2.3 mm long, 0.8–1.3 mm wide, keel 3veined, apex obtuse to slightly mucronate.
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 3: filaments 2–2.1 mm long.
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anthers 1.2–1.9 mm long
Morphology Reproductive morphology Fruits
Nutlet yellowish-brown when young, dark grey with metallic shine when mature, narrowly obovoid to ellipsoid, 0.7–1.1 mm long, 0.3–0.4 mm wide, minute tubercles in longitudinal rows
Ecology
Seasonally flooded grassland, swampy grassland, mangrove edge, woodland; sea-level to 1550 m
Conservation
Least Concern (LC) due to its wide distribution
Note
This species has a very leafy culm base, and is easy to recognize with the narrow long spikelets. The colour of the glumes is highly variable. In the past two varieties have been described based on colour, and glumes in the darker specimens are more open and spreading, and occur more inland. Too many intermediate specimens exist and the varieties are not upheld here.
Distribution
Range: Sierra Leone, Liberia, Ivory Coast, Benin, Nigeria, Equatorial Guinea, Gabon, Congo-Kinshasha, Angola, Malawi, Zimbabwe, South Africa Flora districts: U4 K4 K7 T1 T3 T4 T5 T6 T7 T8 ZP
[FTEA]

J. Browning, K.D. Gordon-Gray†, M. Lock, H. Beentje, K. Vollesen, K. Bauters, C. Archer, I. Larridon, M. Xanthos, P. Vorster, J. Bruhl, K. Wilson and X. Zhang (2020). Flora Zambesiaca Volume: 14: Cyperaceae. M.Á. García, J.R. Timberlake (Eds). Kew Publish

Type
South Africa, Cape, Zeyher 13 (B holotype).
Morphology General Habit
Perennial, densely tufted, up to 73 cm tall, with an erect rhizome covered by often fibrous blackish old leaf bases; culms tufted, 5–68 cm long, 0.6–1.8 mm wide, rounded, striate, glabrous
Morphology Leaves
Leaves up to 33 cm long; leaf sheath straw-coloured to purple, 1.5–7 cm long; leaf blade linear, flat or folded, 5–30 cm long, 1.1–4 mm wide, scabrid on margins and primary vein at least on young leaves, apex acuminate
Morphology Reproductive morphology Inflorescences Bracts
Involucral bracts leaf-like, spreading, the lowermost (1)3–14 cm long, 1.2–2 mm wide
Morphology Reproductive morphology Inflorescences
Inflorescence simply capitate-anthelate, sometimes condensed so as to appear virtually capitate, the primary branches sometimes with a few apical branches, primary branches 3–12, 0.5–5 cm long; spikelets in digitate clusters, sessile and at the end of primary and, occasionally, secondary branches, 5–14 per cluster, linear, 3–19.1 mm long, 0.7–1.3 mm wide, up to 2.5 mm wide with glumes spreading, rachilla straight; glumes glossy, pale reddish-brown to almost black with pale longitudinal lines, ovate, 1.2–2.3 mm long, 0.8–1.3 mm wide, 3-veined, apex obtuse to slightly mucronate; glumes falling off with nutlet
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 3; filaments 2–2.1 mm long; anthers 1.2–1.9 mm long
Morphology Reproductive morphology Fruits
Nutlet yellowish-brown when young, blackish with metallic shine when mature, narrowly obovoid to oblong or ellipsoid, 0.7–1.1 mm long, 0.3–0.4 mm wide, minutely tuberclate in longitudinal rows.
Distribution
Zambia, Zimbabwe, Malawi, Mozambique. Also in Sierra Leone, Liberia, Ivory Coast, Benin, Nigeria, Equatorial Guinea, Gabon, D.R. Congo, Uganda, Kenya, Tanzania, Angola and South Africa.
Ecology
Isoberlinia and Brachystegia woodland; vlei grasslands; usually on sand (often Kalahari Sand); one collection (Wild 7682) from site with ‘highest copper values’; sea-level to 1700 m.
Conservation
Least Concern because of its wide distribution.
Recognition
F.T.E.A. notes that this species has a very leafy culm base; this, with the long narrow spikelets, make it easy to recognize. The colour of the glumes is highly variable. In the past two varieties have been described based on colour, and glumes in the darker specimens are more open and spreading, and occur more inland.
[FZ]

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation
Predicted extinction risk: not threatened. Confidence: confident
[AERP]

Cyperaceae, Miss S. S. Hooper. Flora of West Tropical Africa 3:2. 1972

Morphology General Habit
Densely tufted plant
Morphology Leaves Leaf sheaths
Hard, persistent leaf-sheaths
Morphology Reproductive morphology Inflorescences
A compact inflorescence of short rays bearing spherical spikes of dark, obtuse spikelets
Ecology
Sandy places.
[FWTA]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • Flora Zambesiaca

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Flora of West Tropical Africa

    • Flora of West Tropical Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0