Families of Vascular Plants - EEB337H

Poales - Cyperaceae

122 genera, 4,500 species (98/4350 in Mabberley 1997), especially in temperate habitats; mostly rhizomatous herbs. Leaves often three-ranked, stem triangular in section. Flowers unisexual or bisexual, wind-pollinated, in 1- to many-flowered spikes or spikelets. Placentation basal, the ovule arising from the floral apex. Fruit an achene, the single seed within not joined joined to the ovary wall. Both C3 and C4 photosynthesis, leaf anatomy are present in Cyperaceae. Scarcely palatable to animals (inc. humans) and of virtually no economic importance in comparison with Poaceae; some species are used as food (their tubers) or medicinally (rhizome of Cyperus corymbosus - Mabberley 1997). Thin strips of the leaf pith of Cyperus papyrus laid up side by side and at right angles side by side again to make papyrus (root of the word "paper").

Rhynchospora insect-pollinated (inflorescence bracts partly white)

Compare Cyperaceae to with Poaceae with respect to spikelet and fruit structure

Cyperaceae Interactive Identification Keys - This link is to their illustrated glossary, from which you can also access interactive keys for selected genera.

The Cyperaceae are nearly unique in possessing a suite of unusual cytological fearures (Hipp et al. 2009):

  • (1) chromosomes with diffuse centromeres, such that chromosome breaks result in fragments that are not lost during meiosis
  • (2) post-reductional meiosis
  • (3) microgametophytes (pollen grains) that, like the megagametophytes of most flowering plant families, develop from only one of the four microspores formed by meiosis

One can speculate that chromosome evolution in the Cyperaceae could be an important factor contributing to frquent speciation in the family, particularly in the genus Carex.

CYPERACEAE (classification as in Dahlgren et al. 1985; compare Zomlefer 1994, pp. 350-356);

subfamilies and exemplar Ontario genera (in bold, seen in lab 23-Oct-97).


Flowers perfect (bisexual)

I. Scirpoideae, including:
II. Rhynchosporoideae, including:
III. Mapanioideae (wet tropics)

Flowers unisexual

IV. Sclerioideae, including:
V. Caricoideae, including:

Also: Blysmus, Lipocarpha

The Flora North America treatment of the Cyperaceae (Ball, Reznicek, Murray 2002) is available HERE:

Flora North America - Cyperaceae


The Families of Flowering Plants
DELTA database in natural language

L. Watson and M. J. Dallwitz


Images from Botany at the University of Hawaii

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Please send your comments to tim.dickinson@utoronto.ca; last updated 24-Oct-2008