Cyperus

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Cyperus

Description

Perennial or annual herbs, tufted or with creeping rhizome. Leaves tristichous, narrowly linear, grass-like, rarely lanceolate or elliptic, the lower ones often scale-like, covering the base of the stem and the rhizome, rarely all reduced to their sheaths. Inflorescence terminal, often anthelate (terminal spike or cluster overtopped by the lateral ones), simple to decompound, umbel-like, not rarely capitate by sup- pression of the rays, in a few spp. truly umbellate. Flowers bisexual, the uppermost of the spikelet often male or barren by reduction; Stamens 3,2, or 1, the median one anterior, the others transversal;

Distribution

Asia-Tropical:, New Guinea present Paleotropical: present Pantropical: present Tropics and subtropics: present
About 600 spp., the vast majority of them in the tropics and subtropics. In Malesia 76 spp., most of them of pantropical or paleotropical distribution. A few spp. are apparently endemic in New Guinea (C. neoguineensis, C. subpapuanus, C. cinereobrunneus, C. meistostylus, C. pachycephalus). Several spp. are very rare in Malesia and show large disjunctions (C ohwii, C. exaltatus, C. alopecuroides, C. bulbosus, C. zollingeri, C. babakan, C. multispicatus, C. teneriffae, C. diaphanus, C. substramineus). Recent introductions are C. aromaticus and C. sphacelatus.

Uses

Economically the genus is unimportant. The dried stems of some spp. (e.g. C. elatus, C. malaccensis, C. procerus) are used for making mats or as strings. C. brevifolius, C. kyllingia, and C. rotundus make rather good pasturage when they are young and grow extensively. C. flabelliformis and C. papyrus are grown as ornamentals in ponds. For C. flabelliformis see p. 618.
Cyperus papyrus L., indigenous in Central tropical Africa, is readily recognizable by its up to 5 m tall, pithy stems at the base covered with bladeless sheaths, the umbellate inflorescence with very numerous, subequal rays, and the lanceolate involucral bracts much shorter than the inflorescence. It was early used for paper-making and cultivated for this purpose in Egypt, Palestine, and S. Europe. See .
The tubers of C. esculentus and C. bulbosus are edible, but their use is not recorded for Malesia.

Notes

Flower-structure in Cyperus is as in those Scirpus spp. which lack hypogynous bristles; Cyperus differs in that the glumes are distichously arranged (spirally in Scirpus). See note under C. pygmaeus, p. 635.
There is no unanimity on the delimitation of the genus (type species C. esculentus L.). C. B. CLARKE, the founder of modern Cyperology, originally took Cyperus in a wide sense, but in his later publications he proposed the following subdivision:
  • 1a. Style 2-branched. 2
  • b. Style 3-branched. 4
  • 2a. Rachilla deciduous Kyllinga
  • b. Rachilla persistent. 3
  • 3a. Nut laterally compressed Pycreus
  • b. Nut dorsally compressed Juncellus
  • 4a. Rachilla persistent Cyperus
  • b. Rachilla deciduous. 5
  • 5a. Rachilla deciduous in one piece. 6
  • b. Rachilla breaking up into as many joints as nuts Torulinium
  • 6a. Glumes not winged Mariscus
  • b. Glumes winged Courtoisia

This classification is artificial in many respects. More recently two other (monotypic) genera have been segregated, Sphaeromariscus CAMUS for C. compactus, and Queenslandiella DOMIN (= Mariscopsis CHERM.) for C. hyalinus.

In VALCKENIER SURINGAR'S excellent revision of Cyperus in the Malay Archipelago (1898), the genus is taken in its wide sense, and so it is in KÜKENTHAL'S monograph in the Pflanzenreich (1935-36). With the exception of Courtoisia the genera accepted by CLARKE were here reduced to subgeneric rank. As also Juncellus, Mariscus and Torulinium are ill-defined even as subgenera, in the present treatment only Cyperus, Pycreus, and Kyllinga are accepted as such. See also .
, studied the embryos of 132 species of Cyperus belonging in different groups. The uniformity of the embryos appears to support the wide conception of the genus.

The function of the cladoprophyll in Cyperus was pointed out by . It is by means of the cladoprophylls that the primary rays of the anthela attain their more or less spreading position.

Before the flowers are fully developed the rays are erect and congested. When mature the tubular prophylls show a prominent swelling at their base on the adaxial side. This swelling consists of a rapidly developing tissue without chlorophyll. By the rapid growth of this local tissue the rays are pushed away from the central axis.

Citation

STEUD. - in Syn. 1855: 2
VALCK. SUR., Gesl. Cyp. Mal. Arch. 1898: 41
KÜK. - in Pfl. R. 1935-1936: 41
C. B. CLARKE - in J. Linn. Soc. Bot. 1884: 33
LINNÉ - in Linnaea. 1870: 271
BOECK. - in Linnaea. 1868: 436
B. & H. - in Gen. Pl. 1883: 1043
LINNÉ - in Sp. Pl, ed. 1. 1753: 44
MIQ. - in Fl. Ind. Bat. 1856: 254
KUNTH - in En. 1837: 2
KOYAMA - in Quart. J. Taiwan Mus. 1961: 159
PAX - in E. & P., Pfl. Fam. 2. 1887: 107