Cyperus aethiops Welw. ex Ridl.

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/185348/8393266

Conservation

LC - least concern

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

Angola, Huíla Dist., between Ferrao da Sola and Jau, iv.1860, Welwitsch 6875 (BM holotype).

Morphology General Habit

Robust tufted perennial, sometimes forming large clumps; culms 3–10, erect, to 70 cm long and 1–1.5 mm wide, rounded to triangular, smooth

Morphology Leaves

Leaves basal, sheaths to 10 cm long, brown to almost black, with 0.5–2 mm wide mebranaceous ochrea-like flanges; blade rolled (appearing cylindric when dry), to 45 cm long and 0.5–1(1.5) mm wide, scabrid near tip

Morphology Reproductive morphology Inflorescences

Inflorescence a simple umbel-like anthela, often condensed to almost capitate, 1.5–9 × 2–10 cm, open inflorescences with one to several sessile racemose clusters and 2–5(7) stalked clusters, each cluster with 10–25 spikelets; peduncles of stalked clusters 0.5–6.5 cm long; involucral bracts leaf- like (flat at base), 2–3, largest 5–17(25) cm long, 0.5–3 mm wide, scabrid near tip or in upper half

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets 5–15 × 1–2 mm, linear to lanceolate; rachis straight in fruiting stage; glumes about 50% overlapping, appressed or spreading, dark brown to dark purple or shiny black, ovate with very narrow hyaline margin towards apex, 2–3 × 1.5–2 mm, acute sometimes apiculate, keel pale brown

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens (2)3; filaments 1–2 mm long; anthers 1–1.5 mm long

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigma branches 2, 1–2 mm long

Morphology Reproductive morphology Fruits

Nutlet oblong, with truncate to very slightly tapering apex, shortly apiculate, steel grey, 1–1.5 mm long, with numerous minute papillae in longitudinal rows.

Distribution

Botswana, Zambia, Zimbabwe, Malawi, Mozambique. Also in Cameroon, Central African Republic, Sudan, Ethiopia, D.R. Congo, Kenya, Tanzania, Angola, Namibia and South Africa.

Ecology

Swampy grassland, dambos, seepages, often in places liable to burning; 850–2400 m.

Conservation

Widespread distribution; Least Concern. In common and widespread habitats.

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

Type

Type: Angola, District Huilla, Welwitsch 6875 (BM!, syn.), Angola, Welwitsch 7025 (LISU, lecto.; BM!, iso.) [Haines & Lye only mention the last one, which could be taken as a lectotypification]

Morphology General Habit

Perennial up to 90 cm high, slender to robust, with slightly swollen base and many 1–2 mm thick roots.

Morphology Culms

Culms tufted, 21–82 cm long, 0.8–2.2 mm wide, trigonous, smooth, the basal part surrounded by wide blackish leaf sheaths

Morphology Leaves

Leaf sheath brown, 4–9.5 cm long. Leaf blade linear, folded, sometimes channelled, stiff, 18–37 cm long, 1.2–3.8 mm wide, acute to acuminate, apex ± scabrid Leaves up to 45 cm long.

Morphology Reproductive morphology Inflorescences Bracts

Involucral bracts leaf-like, 2–3, 8–12.2 cm long, 1.2–3.2 mm wide, often folded and stiff

Morphology Reproductive morphology Inflorescences

Inflorescence simple (to compound), primary branches 2–4, 1–3 cm long.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets loosely to densely arranged in digitate clusters, sometimes on an elongated axis, the clusters sessile and at the end of primary branches. Spikelets 8–20 to many per cluster, narrowly linearlanceolate to narrowly ovoid, 7.2–15 mm long, 1.5–1.9 mm wide, axis straight to curved.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes brown-black, linear-lanceolate to elliptic, 2.1–2.5 mm long, 1–1.3 mm wide, keel ± acute, (yellowish) green, grooved, 2-veined, apex acute to sometimes ± obtuse

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 3.

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments (0.9–)1.4–1.7 mm long.

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers 0.6–1.3 mm long

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigma 2-branched

Morphology Reproductive morphology Fruits

Nutlet grey, often shiny, oblong-cylindrical to ellipsoid, 0.9–1.1 mm long, 0.3–0.4 mm wide, minute tubercles in longitudinal rows.

Ecology

Swampy grassland; 900–2200 m

Conservation

Least concern (LC) although not widespread in the Flora area, the species is fairly wide distributed, and occurs in a common habitat.

Note

The species closest related to P. aethiops seems to be P. nuerensis. The most obvious differences can be found in the width of the leaves and involucral bracts, the size and colour of the glumes, and the number of stamens per glume.

Distribution

Range: Cameroon, Congo-Kinshasa, Sudan, Ethiopia, Angola, Zambia, Botswana, South Africa Flora districts: K3 T4 T7 T8