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This species is accepted, and its native range is Venezuela, Bolivia.


Rasingam, L., Chorghe, A., Meve, U. et al. 2013. Brachystelma penchalakonense (Apocynaceae: Asclepiadoideae) — a new species from Andhra Pradesh, India. Kew Bulletin 68: 663.

Near Threatened (NT) category of IUCN (2001). Cyperusstergiosii does not appear to be threatened. Specimens document four populations collected, the most recent in 2000. Narrow range and few collections indicate the need for conservation.
Southern Venezuela, and eastern Bolivia.
In shallow water or wet soil of llanos, savannas, palm swamps and pantanos.
Morphology Culms
Culms 2 – 3.5 mm diam., trigonous, smooth
Morphology General Habit
Perennial, cespitose, 75 – 100 cm tall
Morphology General Scales
Floral scales persistent, 2 – 3 (the uppermost sterile, ± involute), 1.7 mm long, ± 1 mm wide, ovate, obtuse, hyaline margined, laterally 2 – 3 nerved, reddish brown to carmine, medially 3-nerved, greenish
Morphology Leaves
Leaves 4 – 6, 30 – 60 cm long, 7 – 12 mm wide, inversely w-shaped, strongly 3-nerved, the margins, and keel and abaxial nerves scabrous
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 3; filaments 1.7 mm long; anthers 0.6 mm long, oblong-ellipsoid, the connective apex not prolonged
Morphology Reproductive morphology Flowers Gynoecium Style
Styles 0.25 mm long; stigmas 3, 0.75 mm long
Morphology Reproductive morphology Fruits
Achenes 1.5 mm long, 0.5 mm wide, trigonous, slightly dorsiventrally compressed, narrowly ellipsoid-oblong, the apex obtuse and apiculate, the base narrowly cuneate, the angles rounded, the faces flat to slightly concave, papillose to puncticulate, light brown
Morphology Reproductive morphology Inflorescences
Rays 6 – 8, (1 –) 4 – 6 cm long Spikes 4 – 6 (some borne on secondary rays up to 1 cm long), 9 – 12 mm long, 5 – 6 mm wide, obovoid and distinctly tapered at the base (not much flattened when pressed); rachis 8 – 10 mm long, not visible when pressed Inflorescence bracts 4 – 6, (3 –) 8 – 40 cm long, (2 –) 8 – 12 mm wide, inversely w-shaped (or flat), the margins and nerves scabrellate, ascendent at about 45°; secondary bracts 1 – 3 cm long, spreading to reflexed
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets 70 – 100, the upper spreading, the lower strongly reflexed, 2 – 2.5 mm long, 0.5 – 0.8 mm wide, oblong-ellipsoid to lanceolate, subterete; rachilla deciduous, 0.2 – 0.3 mm wide, 0.1 – 0.2 mm thick, flexuous, green, wings 0.3 mm wide, hyaline, successive scales about 2.4 mm apart
Following the only modern worldwide monograph of the genus (Kükenthal1935 – 36), this new species is placed in section Turgiduli C. B. Clarke. This section is characterised by perennial habit, dense spikes, and deciduous spikelets, that are turgid to terete and oblong-lanceolate, with a conspicuously winged rachilla. Other neotropical species of this section include Cyperusligularis L., C. guianensis, C. anderssoniiBoeckeler, and C. mutisii Andersson. The new species is most similar morphologically to C. guianensis, which has single spikes that do not taper at their base. Using available accounts for regions where it occurs (e.g., Fedón Ch 2008 and Tucker 1998), it would key to C. ligularis; however, it lacks the papillose leaves and culms and harshly scabrous leaf margins of C. ligularis. Additionally, the spikes of C. stergiosii taper while those of C. ligularis have parallel sides. Other differences are shown in Table 1. The known distribution, in southernmost Venezuela and in eastern Bolivia, suggests that there may be additional populations, and perhaps, unidentified collections from points in between, specifically western Amazonas, Brazil, as well as Amazonian sections of Colombia, Ecuador, or Peru. Named for Basil Stergios (b. 1940), Venezuelan botanist and collector of two of the five known specimens. Cyperusstergiosii is part of Cyperus sect. Turgiduli C. B. Clarke, and is distinguished from its nearest relative, C. guianensis, in having the primary rays of the inflorescence compressed-trigonous, the spikes in sessile groups of 4 – 6 at the end of each ray, and the lower spikelets of each spike strongly reflexed, so that the spike appears distinctly tapered basally.
Flowering and/or fruiting specimens have been gathered in February, March, June, August, and October.
Type: Venezuela: Edo. Portuguesa: Dtto. Guanare: Guanare Río Portuguesa, fundo El Chaparral, caminohacia El Rocio, esteropantano, 26 Aug. 1986, B. Stergios 9340 (holotype MO; isotypes K, PORT not seen).
Vegetative Multiplication Rhizomes
Rhizomes short, horizontal to slightly oblique, less than 6 mm thick

Native to:

Bolivia, Venezuela

Cyperus stergiosii G.C.Tucker appears in other Kew resources:

First published in Kew Bull. 68: 622 (2013)

Accepted by

  • Govaerts, R., Nic Lughadha, E., Black, N., Turner, R. & Paton, A. (2021). The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. Scientific Data 8: 215.


Kew Bulletin

  • Fedón Ch, I. C. (2008). Catálogocomentado del géneroCyperus L. (Cyperaceae) en Venezuela. Fundación Instituto Botánico de Venezuela, Caracas.
  • IUCN (2001). IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland & Cambridge.
  • Kükenthal, G. (1935 – 36). Cyperaceae-Scirpoideae-Cypereae. In: A. Engler (ed.), Das Pflanzenreich IV. 20 (Heft 101). Verlag von Wilhelm Engelmann, Leipzig.
  • Tucker, G. C. (1994). Revision of the Mexican Species of Cyperus L. (Cyperaceae). Syst. Bot. Monogr. 43.
  • Tucker, G. C. (1998). Cyperus (Cyperaceae). In: P. Berry, B. Holst & K. Yatskievych (eds), Flora of the Venezuelan Guayana 4: 523 – 541. New York Botanical Garden.
  • Tucker, G. C. (2007). Systematics of Cyperus L. section DiffusiKunth (Cyperaceae) in the Neotropics. In: L. M. Barbosa & N. A. Dos Santos, Jr. (eds), A Botânica no Brasil: pesquisa, ensino e políticaspúblicasambientais: 311 – 314. SociedadeBotânica do Brasil, São Paulo.

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at and
© Copyright 2017 World Checklist of Selected Plant Families.

Kew Bulletin
Kew Bulletin

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at and
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families.