Cyperus L. 

Literature: There is a vast literature on Cyperus. The monograph of the genus by Kükenthal (1935-1936) has become out-of-date but is still useful. The following additional references are useful for the study of the representatives in western Europe: DeFilipps (1980), Tucker & al. (2002), Castroviejo (2007).

Cyperus is here treated in a broad sense as so include Mariscus Vahl. Pycreus Beauv., with one native species (P. flavescens (L.) Beauv. ex Reichenb.; syn.: Cyperus flavescens L.), was more or less widely accepted as a segregate genus in the past years (see for instance Goetghebeur 1998, Mabberley 2008, Vrijdaghs & al. 2011). However, recent molecular research (Muasya & al. 2002) seems to support a broadly circumscribed genus Cyperus (incl. Pycreus and others). Pycreus is polyphyletic and completely nested in Cyperus; moreover, morphological peculiarities are shared with other members of Cyperus (Laridon & al. 2013). Species of Pycreus (ca. 100) are distinguished by their biconvex, laterally compressed achenes and two stigmas.

As here circumscribed, Cyperus is a genus of ca. 600 species. Most are native in the tropics but many extend to more temperate regions. Only one species, Cyperus fuscus L., is native in Belgium.

1. Plant annual, rarely exceeding 30 cm. Inflorescence axis not winged (native) === Cyperus fuscus

1. Plant perennial, often exceeding 30 cm. Inflorescence axis winged or not === 2

2. Spikelets digitately or stellately arranged, without or with a very short common axis === 3

2. Spikelets arranged in spikes with a conspicuous common axis === 4

3. Leaf blades absent (reduced to the sheaths). Inflorescence bracts numerous (usually at least 20), rigid, horizontal. Stamens 3. Plant usually vigorous, normally exceeding 50 cm === Cyperus involucratus

3. Leaf blades present. Inflorescence bracts less than 10, flaccid, horizontal to ascending. Stamens 1(-2). Plant usually more slender, rarely exceeding 50 cm === C. eragrostis

4. Spikelets 1-2(-3)-flowered === C. cyperoides

4. Spikelets 6-40-flowered === 5

5. Spikelet basally articulated, deciduous as a unit with floral scales and achenes still attached to the rachilla. Inflorescence hemispherical (a globose head). Spikelets very numerous per head (always > 20). Rhizomes never bearing tubers === C. congestus

5. Spikelet rachilla remaining attached to the rachis, not basally articulated. Floral scales and achenes disarticulating from base to apex of the rachilla. Inflorescence never a globose head. Spikelets much less numerous (< 20 per head). Rhizomes often bearing tubers (except in C. longus) === 6

6. Spikelets yellowish, stramineous to golden-brown. Leaves and culms yellow-green. Rhizomes always bearing tubers (not easily uprooted!). Floral scales distinctly 3-4-veined === C. esculentus

6. Spikelets reddish or purplish with contrasting green midrib. Leaves and culms dark green (often slightly glaucous). Rhizomes not or rarely bearing tubers (C. rotundus). Floral scales 2-3-veined  === 7

7. Rhizomes woody, long and thick, never bearing tubers. Plants often vigorous, 50-120 cm tall. Non-weedy plants, often confined to more or less natural habitats === C. longus

7. Rhizomes slender, always bearing tubers. Plants commonly small, rarely exceeding 30 cm. Weedy plants of anthropogenic habitats === C. rotundus

Additional aliens: Cyperus aggregatus (Willd.) Endl. [syn.: C. cayennensis (Lam.) Britton, C. flavus (Vahl) Nees, Kyllinga cayennensis Lam., K. squarrosa Baldwin, Mariscus aggregatus Willd., M. flavus Vahl, M. laevis Kunth] (S-Am., wool alien), C. conglomeratus Rottb. (syn.: C. arundinaceus Forssk.) (Afr., As., wool alien), C. difformis L. (syn.: C. lateriflorus Torrey) (Old World (sub-)trop., wool alien), C. exaltatus Retz. (trop., wool alien), C. imbricatus Retz. (syn.: C. radiatus Vahl) (trop., wool alien), C. longus L. subsp. badius (Desf.) Bonnier et Layens (syn.: C. badius Desf.)  (Old World, wool alien,…), C. longus L. subsp. tenuiflorus (Rottb.) Kük. (syn.: C. tenuiflorus Rottb.) (S-Afr., wool alien), C. reflexus Vahl [syn.: C. arenicola Steud., C. fraternus Kunth, C. pseudovegetus Steud. var. arenicola (Steud.) Kük.] (Am., wool alien), Cyperus rigens J. Presl et C. Presl (Am., wool alien) and C. virens Michaux (Am., wool alien).

Cyperus aggregatus recently also occurred as an alien in imported pot plants in nurseries (Hoste et al. 2009).


Castroviejo S. (2007) Cyperus. In: Castroviejo S. & al. (eds.), Flora Iberica, vol. 23. Real Jardín Botánico, Madrid: 8-27.

DeFilipps R.A. (1980) Cyperus. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 5. Cambridge University Press, Cambridge: 284-288.

Goetghebeur P. (1998) Cyperaceae. In: Kubitzki K. & al. (eds.), The families and genera of vascular plants, vol. 4. Springer, Berlin: 141-190.

Hoste I., Verloove F., Nagels C., Andriessen L. & Lambinon J. (2009) De adventievenflora van in België ingevoerde mediterrane containerplanten. Dumortiera 97: 1-16.

Kükenthal G. (1935-1936) Cypereae. In: Engler H.G.A. (ed.), Das Pflanzenreich 101: 1-671.

Larridon I., Bauters K., Reynders M., Huygh W., Muasya M., Simpson D.A. & Goetghebeur P. (2013) Towards a new classification of the giant paraphyletic genus Cyperus (Cyperaceae): phylogenetic relationships and generic delimitation in C₄ Cyperus. Bot. J. Linn. Soc. 172(1): 106-126.

Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.

Muasya A.M., Simpson D.A. & Chase M.W. (2002) Phylogenetic relationships in Cyperus L. s.l. (Cyperaceae) inferred from plastid DNA sequence data. Bot. J. Linn. Soc. 138: 145-153.

Tucker G.C., Marcks B.G. & Carter J.R. (2002) Cyperus. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 23. Oxford University Press, New York-Oxford: 141-191.

Vrijdaghs A., Reynders M., Muthama Muasya A., Larridon I., Goetghebeur P. & Smets E. (2011) Morphology and development of spikelets and flowers in Cyperus and Pycreus (Cyperaceae). Plant Ecology and Evolution 144: 44-63.

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith