Cyperus denudatus L.f.

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

Type

Type: South Africa, Cape of Good hope, without indication of collector (ubi?)

Morphology General Habit

Perennial, with a 3 cm thick creeping scale-covered rhizome, up to 95 cm tall.

Morphology Culms

Culms tufted, crowded, 19–89 cm long, 0.5–1.6 mm wide, trigonous to slightly triquetrous, smooth

Morphology Leaves

Leaves with leaf sheath reddish-brown to purple, 2–18 cm long. Leaf blade absent or reduced to 1 cm long, then reddish-brown

Morphology Reproductive morphology Inflorescences Bracts

Involucral bracts leaflike, erect to spreading, 2(–3), lowermost 1–4 cm long, 1–2.3 mm wide

Morphology Reproductive morphology Inflorescences

Inflorescence a simple to compound anthela, primary branches 5–12, 1.5–6.6(–16) cm long.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets in digitate clusters, sessile and at the end of primary and secondary branches, 2–5 per cluster, linear-lanceolate, 2.4–8(–20) mm long, 0.9–1.7 mm wide, rachis straight, sometimes slightly curved.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes pale brown to reddish-brown to dark brown, ovate, 1.1–1.7 mm long, 0.6–0.8 mm wide, keel greenish, acute, apex slightly excurrent

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 3.

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments 1.1–1.6 mm long.

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers 0.6–1 mm long

Morphology Reproductive morphology Fruits

Nutlet whitish when young or depauperate, brown when mature, ovoid to obovoid, 0.5–0.7 mm long, 0.3–0.6 mm wide, base cuneate, muricate when young or depauperate. Tuberculate when mature

Ecology

River-sides, flood plains, swamps, damp grassland, moist rock crevices; 0–2000 m

Conservation

Least Concern (LC) due to its wide distribution and common habitat.

Note

Although C. platycaulis var. recedens has been put into synonymy of C. platycaulis by many others, it has more in common with denudatus: slender appearance, shorter glumes and the same colour as denudatus. Haines & Lye state this species is closely related to C. haspan, but differs in having no leaves. Haines & Lye include C. phaeorhizus here, which I (HB) have under haspan. HB: in the protologue of C. denudatus, the taxon is not compared to any other sedge. ‘Culmo triquetro, involucro subnullo.” Hab. ad Caput Bona Spei. ‘Culmus triqueter, bipedalis, vagina unica in medio culmi; umbella composita, non multum expansa; involucrum universale radiis vix manifesto, ut fere nullis, partiale nullum; spicae oblongae, purpurescantes, carina viridi, apice patentiusculae” (sic). Haines & Lye feel maybe denudatus is a variety of haspan – and I (HB) agree that the two are very similar, apart from the absence/presence of leaves character.

Distribution

Range: Widespread on west, central and southern tropical Africa Flora districts: U2 U4 K3 K4 K7 T1 T2 T3 T4 T5 T6 T7 T8

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/185737/120150479

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

South Africa, Cape of Good Hope, without indication of collector (type unknown).

Morphology General Habit

Perennial, with a 3 cm thick creeping scale-covered rhizome, up to 95 cm tall; culms tufted, crowded, 19–89 cm long, 0.5–1.6 mm wide, trigonous to slightly triquetrous, smooth

Morphology Leaves

Leaves with leaf sheath reddish-brown to purple, 2–18 cm long; leaf blade absent or reduced to 1 cm long, then reddish-brown

Morphology Reproductive morphology Inflorescences Bracts

Involucral bracts leaf-like, erect to spreading, 2(3), lowermost 1–4 cm long, 1–2.3 mm wide

Morphology Reproductive morphology Inflorescences

Inflorescence a simple to compound anthela, primary branches 5–12, 1.5–6.6(16) cm long; spikelets in digitate clusters, sessile and at the end of primary and secondary branches, 2–5 per cluster, linear-lanceolate, 2.4–8(20) × 0.9–1.7 mm wide, rachis straight, sometimes slightly curved; glumes pale brown to reddish-brown to dark brown, ovate, 1.1–1.7 × 0.6–0.8 mm wide, keel greenish, acute, apex slightly excurrent

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 3; filaments 1.1–1.6 mm long; anthers 0.6–1 mm long

Morphology Reproductive morphology Fruits

Nutlet whitish when young or depauperate, brown when mature, ovoid to obovoid, 0.5–0.7 × 0.3–0.6 mm wide, base cuneate, muricate when young or depauperate, tuberculate when mature.

Distribution

Botswana, Zambia, Zimbabwe, Malawi, Mozambique. Widespread in west, central and southern tropical Africa.

Ecology

Riverbanks, floodplains, dambos, damp grassland; 900–1750 m.

Conservation

Least Concern on account of its wide distribution.

Recognition

Much confused with Cyperus haspan, of which it is essentially a leafless form. In general, C. denudatus differs in having no leaf blades, or very short ones, in the short involucral bracts, and in more often having a clear elongated rhizome with regularly spaced culms.

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

Type

Types: Tanzania, Lushoto District: Usambara Mts, Kwai, Albers 227 & Eick 112 (B, syn., not found)

Vegetative Multiplication Rhizomes

Horizontal rhizome and dense culms

Morphology Leaves

Leaves 40–50 cm long, 5–6 mm wide

Morphology Reproductive morphology Inflorescences

Inflorescence bracts 2–3 Inflorescence of a simple umbel of spikes, or a congested head, with spikelets of 12 × 3 mm, 8–12-flowered.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes blackish

Morphology Reproductive morphology Flowers Gynoecium Style

Style 3branched

Morphology Reproductive morphology Fruits

Nutlet ovoid, trigonous to pyramidal, papillose-reticulate.

Ecology

Moist sites in grass- and bushland; ± 1600 m

Note

Clarke says closest to C. tenax Boeck. but differing in the much narrower spikelets ‘and the nutlet’

Distribution

Flora districts: T3 Flora districts: Known from the type only

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/44392857/44429423

Conservation

DD - data deficient