Index of Species Information

SPECIES:  Paspalum distichum


SPECIES: Paspalum distichum
AUTHORSHIP AND CITATION : Snyder, S. A. 1992. Paspalum distichum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].

ABBREVIATION : PASDIS SYNONYMS : Paspalum vaginatum Sw. Paspalum paspalodes (Michx.) Scribn. SCS PLANT CODE : PADI6 PAVA COMMON NAMES : knotgrass seashore paspalum salt jointgrass turfgrass TAXONOMY : The currrently accepted scientific name for knotgrass is Paspalum distichum L. (Gramineae) [9]. Although many authorities distinguish the closely related species P. vaginatum, Godfrey and Wooten [11] consider this distinction unwarranted. Paspalum vaginatum and P. distichum will be treated as a single species for the purpose of this report. LIFE FORM : Graminoid FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Paspalum distichum
GENERAL DISTRIBUTION : Knotgrass is common throughout the southeastern states; it occurs as far north as Massachusetts and south into Mexico and South America. It is also narrowly distributed throughout the Southwest and continues north through California to coastal Oregon and Washington, and central Idaho [9]. ECOSYSTEMS : FRES41 Wet grasslands FRES42 Annual grasslands STATES : AL AZ AR CA DE FL GA ID HI LA MD MA MS NV NJ NM NC OK OR SC TN TX UT VA WA MEXICO BLM PHYSIOGRAPHIC REGIONS : 1 Northern Pacific Border 2 Cascade Mountains 3 Southern Pacific Border 7 Lower Basin and Range 14 Great Plains KUCHLER PLANT ASSOCIATIONS : K049 Tule marshes K072 Sea oats prairie K088 Fayette prairie SAF COVER TYPES : NO-ENTRY SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : NO-ENTRY


SPECIES: Paspalum distichum
IMPORTANCE TO LIVESTOCK AND WILDLIFE : Knotgrass is a valuable duck food in the marshes of Louisiana [3]. It is also considered a good forage grass in Arizona [12]. PALATABILITY : NO-ENTRY NUTRITIONAL VALUE : NO-ENTRY COVER VALUE : NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES : Knotgrass is sometimes used to revegetate eroded marshes in Louisiana [14]. It is also used to rehabilitate overgrazed ranges in Arizona. Results of this project have not yet been released [22]. In germination tests, seeds were incubated at 82 to 95 degrees Fahrenheit (28-35 deg C). Fourteen percent germinated in the dark, while 40 percent germinated with 16 hours of light. Ripening can be sped up with dry storage at 122 degrees Fahrenheit (50 deg C). Scarification with acid can increase germination [10]. OTHER USES AND VALUES : NO-ENTRY OTHER MANAGEMENT CONSIDERATIONS : Knotgrass increases in response to grazing [3]. It is useful as a soil binder along streams but can sometimes be troublesome, as it chokes out irrigation ditches [8,12,17].


SPECIES: Paspalum distichum
GENERAL BOTANICAL CHARACTERISTICS : Knotgrass is a native, perennial, rhizomatous graminoid [9]. Its culms are 7 to 20 inches (0.2-0.6 m) high and are sometimes pubescent [17,18]. Usually two racemes are found at the end of the stem. Leaf blades are flat and from 2 to 6 inches (5-15 cm) long. Rhizomes form dense, extensive mats [5]. RAUNKIAER LIFE FORM : Phanerophyte Geophyte REGENERATION PROCESSES : Regeneration occurs mostly from the spreading and sprouting of rhizomes. Creeping stems root at the nodes and give rise to flowering stems [8]. SITE CHARACTERISTICS : Knotgrass is found along fresh and brackish marshes, coastal salt marshes, ponds, ditches, shorelines, beaches, and dunes; and in freshwater wetlands of the semiarid grasslands of the Southwest [4,8,11,18]. Some associates include sea purslane (Sesuvium portulacastrum), beach dropseed (Sporobolus virginicus), Mexican beach peanut (Okenia hypogaea), railroad vine (Ipomoea pes-caprae), sea lavender (Argusia gnaphalodes), beachberry (Scaevola plumieri), bay cedar (Suriana maritima), cordgrass (Spartina spp.), muhly grass (Muhlenbergia spp.), sedge (Carex spp.), horsetail (Equisetum spp.), spikerush (Eleocharis spp.), rush (Juncus spp.), Olney bulrush (Scirpus olneyi), slender wheatgrass (Elymus trachycaulus ssp. trachycaulus), and johnsongrass (Sorghum halpense) [3,4,11,14]. SUCCESSIONAL STATUS : Knotgrass replaces marshbay cordgrass (Spartina patens) and Olney bulrush in Gulf Coast marshes where grazing has reduced these species. Knotgrass is then replaced by "annuals and unpalatable forbs" [1]. Along the southern Florida coast south of Cape Canaveral, knotgrass along with pink-flowered railroad vine may recolonize the upper beach from the foredune after storm erosion [11]. SEASONAL DEVELOPMENT : Knotgrass flowers and produces fruit between June and November [15,18].


SPECIES: Paspalum distichum
FIRE ECOLOGY OR ADAPTATIONS : Rhizomes generally enable knotgrass to survive fire. POSTFIRE REGENERATION STRATEGY : Rhizomatous herb, rhizome in soil


SPECIES: Paspalum distichum
IMMEDIATE FIRE EFFECT ON PLANT : Fire probably topkills knotgrass. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Knotgrass sprouts from rhizomes following fire [21]. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : Prescribed fires were conducted annually in northern Florida on sites where Paspalum species were present in the understory. Some plots were burned annually, some every second winter, some every third, some every fourth, etc. through 12 winters. Annual and biennial burning maintained the highest grass covers; cover declined sharply starting with fires every third year [21]. FIRE MANAGEMENT CONSIDERATIONS : Fire can be used to reduce litter and increase plant vigor and production in grasses. Fire can also be used to maintain open grasslands by preventing establishment of woody vegetation [21].


SPECIES: Paspalum distichum
REFERENCES : 1. Allan, Philip F. 1950. Ecological bases for land use planning in Gulf Coast marshlands. Journal of Soil and Water Conservation. 5: 57-62, 85. [14612] 2. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434] 3. Chabreck, Robert H. 1968. The relation of cattle and cattle grazing to marsh wildlife and plants in Louisiana. Proceedings, Annual Conference Southeastern Association of Game and Fish Commissioners. 22: 55-58. [14503] 4. Cross, Anne Fernald. 1991. Vegetation of two southeastern Arizona desert marshes. Madrono. 38(3): 185-194. [16107] 5. Duncan, Wilbur H.; Duncan, Marion B. 1987. The Smithsonian guide to seaside plants of the Gulf and Atlantic Coasts from Louisiana to Massachusetts, exclusive of lower peninsular Florida. Washington, DC: Smithsonian Institution Press. 409 p. [12906] 6. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 7. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 8. Godfrey, Robert K.; Wooten, Jean W. 1979. Aquatic and wetland plants of southeastern United States: Monocotyledons. Athens, GA: The University of Georgia Press. 712 p. [16906] 9. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. [1168] 10. Huang, W. Z.; Hsiao, A. I. 1987. Factors affecting seed dormancy and germination of Paspalum distichum. Weed Research. 27(6): 405-416. [17412] 11. Johnson, Ann F.; Barbour, Michael G. 1990. Dunes and maritime forests. In: Myers, Ronald L.; Ewel, John J., eds. Ecosystems of Florida. Orlando, FL: University of Central Florida Press: 430-480. [17394] 12. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2d ed. Berkeley, CA: University of California Press. 1085 p. [6563] 13. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 14. Lehto, Bruce; Murphy, Jeff. 1989. Effects of drawdown and water management on a seriously eroded marsh. U.S. Fish and Wildlife Service: Biological Report. 89(22): 164-169. [17337] 15. Lonard, Robert I.; Judd, Frank W. 1989. Phenology of native angiosperms of South Padre Island, Texas. In: Bragg, Thomas B.; Stubbendieck, James, eds. Prairie pioneers: ecology, history and culture: Proceedings, 11th North American prairie conference; 1988 August 7-11; Lincoln, NE. Lincoln, NE: University of Nebraska: 217-222. [14049] 16. Lyon, L. Jack; Stickney, Peter F. 1976. Early vegetal succession following large northern Rocky Mountain wildfires. In: Proceedings, Tall Timbers fire ecology conference and Intermountain Fire Research Council fire and land management symposium; 1974 October 8-10; Missoula, MT. No. 14. Tallahassee, FL: Tall Timbers Research Station: 355-373. [1496] 17. Mason, Herbert L. 1957. A flora of the marshes of California. Berkeley, CA: University of California Press. 878 p. [16905] 18. Munz, Philip A. 1973. A California flora and supplement. Berkeley, CA: University of California Press. 1905 p. [6155] 19. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843] 20. U.S. Department of Agriculture, Soil Conservation Service. 1982. National list of scientific plant names. Vol. 1. List of plant names. SCS-TP-159. Washington, DC. 416 p. [11573] 21. Vogl, Richard J. 1973. Fire in the southeastern grasslands. In: Proceedings, annual Tall Timbers fire ecology conference; 1972 June 8-9; Lubbock, TX. Number 12. Tallahassee, FL: Tall Timbers Research Station: 175-198. [8466] 22. Wolden, Lynn; Stromberg, Julie; Patten, Duncan; Richter, Holly. 1990. Understory restoration in three riparian forest types. Restoration & Management Notes. 8(2): 116-117. [13790] 23. Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT; RWU 4403 files. 7 p. [20090]

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