Cyperaceae

Plant Sex: Plants monoecious, dioecious (rarely), or flowers bisexual.

Flowers: Actinomorphic. Perianth either absent or present only as scales, bristles, or a PERIGYNIUM in Carex. Flowers are solitary, enclosed by scales or bracts. Style number (2 or 3) reflects carpel number.

Inflorescence: Spikelets in racemes, spikes or panicles. Staminate and carpellate inflorescences often borne on separate branches.

Fruits: Achenes or nutlets. Triangular or lenticular (lens-shaped) in cross section. Style base sometimes persistent (Eleocharis).

Habit: "Grasslike" perennial herbs, often of marshy habitats. Leaves 3-ranked, flat and channeled, sometimes with leaf sheath. Stem often triangular in cross section (but not always!). Internodes solid, i.e. with pith.

Examples:

Carex (sedge)

Carex has 1500 to 2000 species worldwide. There are 142 species of Carex in Illinois! But the species do have morphological character differences, so with a bit of work one can learn to recognize the differences among the species. The following four species can all be seen around SIUC campus lake.

C. blanda. Shoot showing carpellate and staminate inflorescences. Carpellate flowers with perigynia opened up.
C. crinita. Habit of plants. Inflorescences.
C. jamesii. An easily recognized species. Note the small staminate inflorescence and only a few perigynia making up the carpellate inflorescence.
C. lurida. This species has a larger carpellate inflorescence with many perigynia.

Cyperus (sedge)

C. papyrus. Inflorescences of the species used to make papyrus (paper). Plants growing near water. Inflorescences.
C. alternifolius. Habit of plants called the umbrella sedge. Dissected spikelet.
C. esculentus var. sativus. Tubers from chuffa (or tiger nut), used to flavor drinks in Spain.
C. strigosus (nut sedge). This species can be weedy. Plant with inflorescence. Closer view of inflorescence and tiny spikelets.

Scirpus (bullrush)

S. atrovirens. Flowering shoot.
S. validus. Inflorescence. Close-up of dissected staminate and carpellate flowers.

Rhynchospora (beaked rush)

R. colorata. Inflorescence.
R. latifolia. Inflorescence.

Cladium

C. jamaicense (sawgrass). Habit of the plant in the Bahamas. Infructescences.

Eleocharis (spikerush)

E. ovata. Fruiting shoots.
E. palustris. Inflorescence showing styles and stamens emerging from top flowers.
E. acicularis. Flowering shoots. Stem bases showing characteristic red pigmentation.

Eriophorum

E. sp. Habit of the plants growing in Norway. Closer view of the inflorescence - pretty for a sedge!

SIUC / College of Science / Elements of Plant Systematics
URL: http://www.plantbiology.siu.edu/PLB304/Lecture26Poales/Cyperaceae.html
Last updated: 27-Apr-09 / dln