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Home , Carex, Cyperaceae, Cyperus, Cyperus rotundus, Kyllinga, Rhynchospora colorata

Weedy Sedges () of the World Charles T. Bryson and Richard Carter USDA-ARS, Southern Science Research Unit, Stoneville, MS 38776, and Valdosta State University, Valdosta, GA 31698

Cyperaceae is a cosmopolitan of an estimated 5000 Purple nutsedge ( rotundus L.), yellow nutsedge (C. and 100 genera (Ball et al. 2002). Members of esculentus L.), rice flatsedge (C. iria L.), and smallflower Cyperaceae are commonly called sedges. Sedge umbrellasedge (C. difformis L.) are still considered the worst Oxycaryum cubense adversely affect agriculture and forest, urban, and natural areas sedge weeds in agriculture (Holm et al. 1977; Bryson and throughout the world. The number of sedges considered to be Carter In Press). Sedges, such as deeprooted sedge (C. weeds has increased more than twofold in the past 40 years. entrerianus Boeckler), have spread rapidly in the past 20 years Based upon a survey of more than 30 floras, weed lists, and and now infest agriculture, forests, rangelands, and urban and Cyperus entrerianus obtusa other selected publications, we have found references to 429 natural areas (Carter & Bryson, 1996). sedge species in 19 genera (Table 1) that have been reported as californicus weeds (Bryson and Carter In Press). Most sedge weeds are in the genera Cyperus, , Eleocharis, , , Schoenoplectus, , and .

Cyperus iria

Scirpus cyperinus

Although it may be possible to identify immature, sterile specimens of well known sedges like purple and yellow

nutsedge, reliable identification of most sedges to species maculata requires mature, fertile specimens and oftentimes the Cyperus rotundus assistance of a taxonomic expert. (in cotton) Based on our extensive literature review and research efforts over the past three decades, it is readily apparent that sedges are extremely important weeds of agriculture, forest, urban, Table 1. Numbers and percentages of cyperaceous weeds by from Bryson and Carter (In Press). and natural areas. The increased number of sedges considered Cyperus entrerianus weeds over the past two decades suggests that additional sedge Genus Species Percent of Total Cyperusa 144 34 species may become weedy in the future. This indicates a LITERATURE Carex 80 19 In most cases, sedge genera are either C3 or C4; however, five need for increased research into the reproductive biology, Eleocharis 50 12 genera, Abildgaardia, Cyperus, Eleocharis, Fimbristylis, and physiology, growth characteristics, and environmental Baker, H. G. 1965. Characteristics and modes of origin of weeds. Pp. Fimbristylis 37 9 147—172 in H. G. Baker & G. L. Stebbins (editors), The genetics of Rhynchospora, have both C3 and C4 species (Table 3). Of tolerances of sedges to determine which sedges may be safely Scleria 23 5 these, the mostly aquatic to subaquatic Eleocharis is almost colonizing species. Academic Press, NY. Schoenoplectus 20 5 used as ornamentals and where and which species will likely Baker, H. G. 1974. The evolution of weeds. Annual Rev. Ecol. Syst. 5: 1— Rhynchospora 19 4 entirely C3, and all of the subgenera of Cyperus are C4 except become invasive. Research is also needed to develop methods 24. Kyllinga 13 3 Pyncnostachys (=Protocyperus). Although many weeds are Ball, P. W., A. A. Reznicek & D. F. Murray. 2002. Cyperaceae. Pp. 3—8 in 9 2 to control and eradicate recently established invasive sedges. not, some of the most competitive ones are characterized by P. W. Ball, K. Gandhi, R. W. Kiger, D. Murray, J. L. Zarucchi, A. A. 9 2 8 2 C4 photosynthesis (Black et al., 1969; Elmore & Paul, 1983). Reznicek & J. L. Strother (editors), Flora North America, vol. 23. Oxford Univ. Press, . 5 1 Purple and yellow nutsedge and rice flatsedge are C4 ; Lipocarpha 4 <1 smallflower umbrellasedge is C (Hesla et al., 1982). Thus, Black, C. C., T. M. Chen & R. H. Brown. 1969. Biochemical basis for 2 <1 3 competition. Weed Science 17: 338—344. 2 <1 presence of C4 photosynthesis is but one characteristic Bruhl, J. 1993. Sedge genera of the world (Version 2.01), Intkey, Abildgaardia 1 <1 promoting increased competitive ability in sedge weeds. Interactive Dataset. N.C.W. Beadle Herbarium, University of New Courtoisina 1 <1 a, b England, Armidale, New South Wales, Australia. Table 3. C and C photosynthesis in genera of weedy sedges . 1 <1 3 4 Bruhl, J. 1995. Sedge genera of the world: relationships and a new Oxycaryum 1 <1 Cyperoideae b Abildgaardieae classification of the Cyperaceae. Australian Systematic Bot. 8: 125— [Pycreus] 1 <1 Cyperus prolifer Abildgaardia C3/C4 Total 429 100 305. Fimbristylis C3/C4 a Bryson, C.T. and R. Carter. In Press. The Significance of Cyperaceae as Includes Diclidium, Juncellus, Mariscus, Pycreus, and Queenslandiella. Bulbostylis C4 b Cyperus decumbens E. Govindar, the name for a different species from published in Weeds. Sedges: Uses, Diversity, and Systematics of the Cyperaceae, 1973, prevents legitimate transfer of this name under Cyperus. Cypereae eds. R. F. C. Naczi and B. A. Ford. Monographs in Systematic Courtoisina C3 from the Missouri Botanical Garden. Historically, natural barriers and restricted migration routes Cyperus Carter, R. & C. T. Bryson. 1996. Cyperus entrerianus: a little known prevented plants from dispersing over great distances. The subg. Cyperus C4 subg. Diclidium C4 aggressive sedge in the southeastern . Weed Technol. 10: current speed and ease of world transportation by humans and subg. Juncellus C4 232—235. subg. Mariscus C4 cargo has increased the rate and distance of dispersal of plants, Elmore C. & R. Paul. 1983. Composite list of C4 weeds. Weed Sci. 31: subg. Pycreus C4 686—692. including many sedge species. Of the 429 reported weedy subg. Pycnostachys (=Protocyperus) C3 subg. Queenslandiella C4 Carex brysonii Cyperus pilosus Hesla, B. I., I. L. Tieszen & S. K. Imbamba. 1982. A systematic survey of sedges, 107 species (~ 25%) are known or suspected to be (ornamental only) Kyllinga C4 C3 and C4 photosynthesis in the Cyperaceae of Kenya, East . dispersed by humans and pose problems in areas other than their Lipocarpha C4 Photosynthetica 16: 196—205. place of origin (Bryson and Carter In Press) (Table 2). In a Scirpeae Bolboschoenus C3 Table 4. Weed characteristics, many important for weedy sedge survival, Holm, L.G., D. Plucknett, J. V. Pancho & J. P. Herberger. 1977. The survey of horticultural literature, we have found references to Eleocharis C3/C4 spread, and competitiveness. Adapted from Baker (1965, 1974), Bryson World’s Worst Weeds: Distribution, and Biology. University Press of 152 species of sedges used as ornamentals or otherwise Fuirena C3 and Carter (In Press), Muenscher (1955), Radosevich & Holt (1984), Hawaii, Honolulu. Isolepis C3 Stuckey & Barkley (1993), Rejmanek (1996), and Westbrooks (1998). Holm, L. G., J. V. Pancho, J. P. Herberger & D. L. Plucknett. 1979. A cultivated (Bryson and Carter, In Press). This was Oxycaryum C3 Schenoplectus C3 Geographical Atlas of World Weeds. John Wiley & Sons, New York. Copious production of small unanticipated. Of particular interest is the growing horticultural Scirpus C3 Early maturation Muasya, A. M., J. J. Bruhl, D. A. Simpson, A. Culham & M. W. Chase. Caricoideae emphasis on sedges, especially Carex and Cyperus species, as Extended dormancy and discontinuous germination Schoeneae 2000a. Suprageneric Phylogeny of Cyperaceae: A combined analysis. Germination and survival in a wide range of environments ornamentals. Cladium C3 Pp. 593—601 in K. L. Wilson & D. A. Morrison (editors), Monocots: Long life of propagules in soil or during dispersal Lepidosperma C3 Systematics and evolution. CSIRO Publishing, Collingwood, Victoria. Table 2. Numbers and percentages of species by genus of cyperaceous Rhynchosporeae Profuse vegetative reproduction and fragmentation Rapid growth Muenscher, W. C. 1955. Weeds. 2nd Ed. Cornell University Press, Ithaca, weeds that are known or suspected to be dispersed by humans from Bryson Rhynchospora C3/C 4 Sclerieae Short juvenile period New York. and Carter (In Press). Self-compatible or cross-pollinated by wind or unspecialized floral visitors Scleria C3 Radosevich, S. R. & J. S. Holt. 1984. Weed Ecology. John Wiley & Sons. Genus Species Percent of Total Cariceae Survival and the ability to produce seed under adverse environmental conditions a Seed size similar to associated crops or native plants Rejmanek, M. 1996. A theory of seed plant invasiveness: the first sketch. Cyperus 44 39 Carex C3 Structural modifications (e.g., thorns, prickles, spines, urticating hairs) that cause injury Biol. Conservation. 78: 1771—181. Carex 21 20 and repel animals or herbivores a Soros, C. L. & Bruhl, J. J. 2000. Multiple Evolutionary Origins of C4 Fimbristylis 9 9 Data on photosynthetic pathway from Bruhl (1993, 1995), Vorster (1996), Soros & Structural modifications facilitating dispersal Bruhl (2000). Photosynthesis in the Cyperaceae. Pp. 629—636 in K. Wilson & D. A. Eleocharis 8 7 High photosynthetic rate (C4 photosynthesis) b Subfamily and tribal classification follows Bruhl (1995) and Muasya et al. (2000a). Morrison (editors), Monocots: Systematics and Evolution, Royal Schoenoplectus 6 6 Increased water-use efficiency (C4 photosynthesis) Scirpus 6 6 Production of toxic secondary compounds that deter herbivores Botanic Garden, Kew. Kyllinga 5 5 Invasive weeds possess a variety of characteristics enabling Production of phytotoxins to prohibit or suppress growth of other plants () Stuckey, R. L. & T. M. Barkley. 1993. Weeds. Pp.193—198 in N. R. Morin Rhynchospora 3 3 them to disperse rapidly into new areas and out-compete Ability to parasitize other plants (editor), Flora of North Amrerica. Volume 1. Oxford University Press, Accumulation of large food reserves in roots, , or other plant structures Fuirena 2 2 crops, or native or desirable non-native vegetation for light, Alternate host for insect pests and pathogens of crops NY. Bulbostylis 1 1 water, nutrients, and space (Westbrooks, 1998). To varying Resistance to pathogens Vorster, P. 1996. Justification for the generic status of Courtoisina Isolepis 1 1 degrees, many characteristics contribute to the success and Small inconspicuous (Cyperaceae). Bot. J. Linn. Soc. 121: 271—280. Lipocarpha 1 1 Short-and long-range dispersal mechanisms Westbrooks, R. G. 1998. Invasive Plants, Changing the Landscape of Total 107 100 competitiveness of invasive weeds, and sedges share many of Tolerant to environmental and chemical extremes, including fire, , soil disturbances America: Fact Book. Federal Interagency Committee for the a Includes Diclidium, Juncellus, Mariscus, Pycreus, and Queenslandiella. these traits with other plants (Table 4). Management of Noxious and Exotic Weeds, Washington, D.C.