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Species Name:    Urochloa mutica
Common Name:             Para Grass

 

I. TAXONOMY

Kingdom Phylum/Division: Class: Order: Family: Genus:
Plantae Magnoliophyta Liliopsida Cyperales Poaceae Urochola



The non-native plant para grass, Urochloa mutica. Photo courtesy UF/IFAS Center for Aquatic and Invasive Plants. Photographer Ann Murray.

  

The non-native plant U. mutica. Photo courtesy UF/IFAS Center for Aquatic and Invasive Plants. Photographer Vic Ramey.

Species Name: 
Urochloa mutica (Forssk.) T.Q. Nguyen

Common Name(s):
Para GYrass, Mauritius Signal Grass, Pasto Pare, Malojilla, Gramalote, Parana.

Synonymy:
Brachiaria mutica (Forsk.) Stapf
Brachiaria purpurascens (Raddi) Henr.
Panicum muticum Forsk.

Species Description:
Para grass, Urochloa mutica is a plant species found in the IRL watershed and elsewhere in Fllorida but not native to the United States. It is a robust perennial that can grow to 1 m or taller. It is stoloniferous (has horizontal stems, called stolons). The lower portions of the stems have roots at swollen, hairy nodes and spread horizontally and then upwards.

The leaves can grow to 30 cm long and are typically 10-15 mm wide. A row of short, stiff hairs called the ligule occurs at the junction of the leaf sheath and blade. The inflorescence grows as a primary axis and is arranged altternate with numerous spikelets that are about 3 mm long with a purple tint (Langeland and Burks 1997).


Potentially Misidentified Species:
Identification of grasses in general is often difficcult, usually relying on detailed examination of of the rhizomes, leaves, and inflorescence.


II. HABITAT AND DISTRIBUTION 

Regional Occurrence:
Native to Africa, Urochloa mutica has been collected from several U.S. states including Alabama, Florida, Hawaii, South Carolina, and Texas.

In peninsular Florida, para grass is a widespread marginal plant found around lakes, marshes and rivers (Richerson and Jacono 2003).

IRL Distribution:
Urochloa mutica is established in most central and south Florida counties. The FLEPPC Early Detection and Distribution (EDD) Mapping System indicates that positive occurrence records for para grass exist for all IRL watershed counties except St. Lucie County.


III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Urochloa mutica is a perennial grass that can reach 2 m in height, although 1 m is more common.

Abundance:
Richerson and Jacono (2003) report that Urochloa mutica is established and abundant throughout peninsular Florida drainages, and is especiallly problematic in drainage canals. These authors note that several thousand para grass-infested hectares of land around Lake Okeechobee have burned in past wildfires.

Reproduction:
Urochloa mutica can reproduce sexually from seed, but more important is its ability to reproduce vegetatively by means of its above-ground creeping stolons (Tarver et al. 1986, Hoyer et al. 1996).

Embryology:
Although Urochloa mutica has been characterized as a prolific seed producer (> 1,000 seeds per square meter), the germination rate is usually extremely low (Smith 1973).


IV. PHYSICAL TOLERANCES

Temperature:
Urochloa mutica thrives under warm, moist conditions, and is extremely frost intolerant. Wheeler (1950) indicates para grass will not persist at temperatures lower than 8°C. Allen and Cowdry (1961) indicate a minimum temperature for growth of 15°C and Russell and Webb note that 21°C is the optimum mean growth temperature.

Hydrology:
Urochloa mutica grows best under high rainfall conditions in the tropics and subtropics. It can survive seasonal dry conditions by relying on the residual moisture of the marshy habitats it prefers (FAO).


V. COMMUNITY ECOLOGY

Trophic Mode:
Autotrophic (photosynthetic).

Associated Species:
Although Urochloa mutica is quite capable of displacing co-occurring plants, it often does grade into stands of other species, e.g., along an upward distribution from marsh to more upland habitat.


VI. INVASION INFORMATION

Invasion History:
The exotic grass Urochloa mutica is native to Africa where it has a long history of cultivation as a forage species. It was intentionally introduced to the U.S. for this purpose, initially in the 1870s (Austin 1978). It has since escaped cultivation and has become established throughout most of peninsular Florida. It thrives particularly well in agricultural lands and other disturbed habitats (Godfrey and Wooten 1979).

Austin (1978) notes that para grass was employed as camouflage around military installations in south Florida during World War II.

Potential to Compete With Natives:
Though most often found in human-altered habitats, Urochloa mutica is a vigorous plant and is capable of displacing significant amounts of native vegetation. Concern over the potential ecological impact of para grass is warranted given the number of Florida wetland ecosystems in which the species may thrive if it gains a foothold (Austin 1978).

Possible Economic Consequences of Invasion:
Para grass has proved to be an aggressive invader of human-altered habitats in Florida, particularly low-lying ungrazed pastureland and in sugar cane fields. Marginal stands and floating mats of para grass can slow of clog drainage ditches and irrigation canals, and may also impede the navigation of small craft in shallow waterways (Austin 1978, Tarver et al. 1986, Hoyer et al. 1996).


VII. REFERENCES

Allen G.H., and W.A.R. Cowdry. 1961. Yield from irrigated pasture in Burdekin, Queensland. Agricultural Journal 87:207-13.

Austin D.F. 1978. Exotic plants and their effects in southeastern Florida. Environmental Conservation 5:25-34.

Godfrey R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States. Monocotyledons. The University of Georgia Press, Athens, Georgia. 933 p.

Hoyer M.V., Canfield D.E., Jr., Horsburgh C.A., and K. Brown. 1996. Florida Freshwater Plants - A Handbook of Common Aquatic Plants in Florida Lakes. University of Florida, Institute of Food and Agricultural Sciences, Gainesville, Florida. 264 p.

Richerson M.M., and C.C. Jacono. 2003. Urochloa (Brachiaria) mutica (Forsk.) T.Q. Nguyen. USGS Nonindigenous Aquatic Species fact sheet. Available online.

Russell J.S., and H.R. Webb. 1976. Climatic range of grasses and legumes used in pastures. Result of a survey conducted at the 11th International Grassland Congress. J. Aust. Inst. Agri. Sci., 42:156-163.

Smith R.N.W. 1973. Para grass in Northern Territory -parantage and propogation. Tropical Grasslands Vol 7249-250.

Tarver D.P., Rogers J.A.,. Mahler M.J, and R.L. Lazor. 1986. Aquatic and Wetland Plants of Florida. Third Edition. Florida Department of Natural Resources, Tallahassee, Florida. 127 p.

Wheeler W.A. 1950. Forage and Pasture Crops. van Nostrand Publishers, New Jersey. 752 p.

Report by: J. Masterson, Smithsonian Marine Station
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Page last updated: December 1, 2007