Cogongrass occurs in southeastern pine and oak-pine communities that experience frequent fire see Cogongrass in North America for further details. Brazilian satintail is rhizomatous, with a mat-like growth form [ 43]. Some researchers report cogongrass as highly productive [ 43 ], but flowering is often sporadic, ranging from none to frequent flowering within and among populations [ 3443, ]. In Peru, Brazilian satintail dominates montane savannas. Shilling and others [ ] showed that wind can disperse cogongrass spikelets up to feet m from the parent plant.
Common groundlayer associates include big bluestem Andropogon gerardiipaintbrush A. Brazilian peppertree Schinus terebinthifolius and silkreed Neyraudia reynaudiana are other nonnative invasive associates inventoried on Everglades savannas. This review treats Brazilian satintail and cogongrass as 2 distinct species. Field and greenhouse studies suggest that cogongrass flowering is not photoperiod-dependent [ ].
More than 1, acres ha of cogongrass were planted for livestock forage and soil stabilization in Florida the late s and s [ 32]. Groundlayer associates include hemlock-rosette grass Dichanthelium sabulorum and flatsedge Cyperus hermaphroditus [ 54 ]. Clonal populations show low or no fertility [ 94 ]. The authors concluded that successful outcrossing was low in most cogongrass populations, but higher rates of genetic diversity and fecundity could be expected as southeastern populations expand and outcross [ ]. Imperata brasiliensis, I.
The scientific name of cogongrass is I. Some authorities recognize 5 varieties of cogongrass; according to that treatment, I. Gabel within [ 9 ] ,[ 43 ] does not recognize varieties of cogongrass. Details of Brazilian satintail communities of South America are also limited. Disturbances including nitrogen amendment, slashing, burning, defoliation, and grazing may trigger cogongrass flowering [ 4363 ].
Seed production and seed viability likewise vary widely among populations. Cogongrass's growth habit is loose to clumped, compacted aerial stems arising from the dense rhizome mat [ 3543 ].
Transported rhizome fragments also contribute to its long-distance dispersal and colonization [ 86 ]. Some systematists consider the 2 species synonymous [ 2557 ].
Future of cloud
Dense stands may form monocultures [ 4387 ]. Pollination: Cogongrass is pollinated by wind [ 94]. The leaves have a characteristic white midrib that is set off-center. Basal leaves are 0. Preliminary investigations in Florida found flowers growing under stressful conditions rarely produced seed, so cogongrass has sometimes been labeled as a poor seed producer [ 37]. It is most common in coastal counties of the Southeast, although it has scattered inland occurrences [ 9 ]. A Malaysian study found heavy flower production followed by low seed set [ ]. Flower production: Cogongrass flower production is highly variable.
Some rhizomes grow as deep as 3 feet 1 m [ 8].
Scott [ ] lists associated plant species on Brazilian satintail-dominated savannas of eastern Peru. These characteristics overlap [ 4386 ], however, and it is likely that the 2 grasses have been misidentified in the Southeast [ 86 ]. Leaves are mostly basal, growing from the rhizomes. Photo by Kazuo Yamasaki. Populations with low genetic diversity tended to have low seed viability, while populations with high genetic diversity had high seed viability.
The seeds are small and light weight, with long, hairy plumes aiding wind carriage [ 4394, ]. The inflorescence is a dense, 4- to 8-inch cm panicle of paired spikelets. It is most common in the ground layer of mesic longleaf pine Pinus palustris savannas [ 14 ]. Brazilian satintail also occurs in Puerto Rico and the West Indies [ 4472 ].
Being high in silica [ 26 ], cogongrass leaves are coarse in texture [ 26]. The inflorescence is a 3- to 8-inch cmterminal panicle [ ]; the fruit is a caryopsis. The 2 species occur in similar habitats in the Southeast [ 3764 ].
Brazilian satintail is lesser known, and hence more poorly described, in the United States compared to cogongrass. Copperleaf Acalypha spp. Fire, tillage, mowing, and cold stress may stimulate cogongrass flower and seed production [ ]. Cogongrass dominates some grassland sites in the Everglades [ ]. Oaks including blackjack oak Q. Common shrub associates of cogongrass include persimmon Diospyros virginianablack highbush blueberry Vaccinium fuscatumdwarf huckleberry Gaylussacia dumosaand bitter gallberry Ilex glabra.
It is not known whether low seed viability was due to inability to outcross, poor environmental conditions, or other factors. In central Florida, Gaffney [ 43 ] found cogongrass rhizomes were restricted to the top 4 to 6 inches cm of soil on a phosphate mine site, but grew down to 30 inches 80 cm below ground on a clay settling pond site [ 43 ]. The seeds are small The root system is fibrous. Both seed and rhizome regeneration are important in its spread. These lists may not be exhaustive.
Its distribution may overlap with cogongrass in Florida [ 64 ] and possibly elsewhere in the Southeast [ 57, ]; however, Hall [ 57 ] considered it eliminated in Florida in It is nonnative and invasive throughout other tropical regions of the world. Because there is little English-language literature currently available on Brazilian satintail, this review provides information mostly on cogongrass.
Rhizome and root depths vary with substrate. Leandra Leandra australis and cappel Palicourea spp. Hitchcock [ 61 ] listed cogongrass as present in Oregon inalthough it has not been collected in Oregon for decades.
Cogongrass spread in Alabama from to was apparently due to northeasterly prevailing winds from the Gulf of Mexico blowing seeds up Interstate 65 . Breeding system: Cogongrass is outcrossing [ 4350, ]. Elsewhere in North America, it is present but nonnative in the Gulf Coast states from eastern Louisiana to South Carolina excluding Georgia, where it does not occur [ 392572]. Rhizomes are transported by machinery and fill dirt during construction [ 43].
National gang threat assessment
Hall [ 57 ] suggests that Brazilian satintail be classified as an infrataxon within I. Gabel [ 943 ] separates the taxa as 2 distinct species based upon continents of origin and morphological, cytological, and genetic attributes. A Florida study found that geographically isolated cogongrass populations did not produce seed, but plants within the population produced fertile seeds when cross-pollinated with pollen from another population [ 94 ].
Pertinent information on Brazilian satintail is included whenever possible. In a common garden study using Malaysian collections, some cogongrass populations frequently produced flowers; others never produced flowers but spread vegetatively ; while most produced flowers only after mowing disturbance [ ]. A few small upper leaves occur on the pedestal [ 25].
There were 2 known locations of cogongrass introduction in the United States: 1 from Japan to Alabama inas packing material in a shipment of Unshu orange Citrus reticulata trees; and another from the Philippines to Mississippi inas a possible forage grass [ 3344, ]. Seed reproduction allows for long-distance dispersal and colonization, whereas rhizome spread is the primary means of population expansion [ 5664 ].
Cogongrass rhizomes are "tough and scaly," with short internodes forming a dense underground mat. It has slender, erect culms from 14 to 29 inches cm tall. Imperata cylindrica var. Brazilian satintail and cogongrass are morphologically and genetically very similar, and their hybrids produce fertile offspring [ 57, ]. Brazilian satintail and cogongrass are both nonnative, rhizomatous perennial grasses that are similar in appearance.
Cogongrass rhizomes develop in 2 stages: primary seedling rhizomes, and secondary rhizomes that sprout from seedling rhizomes [ 43 ]. Hybridization, introgression, and overlapping morphological characters often cause taxonomic confusion between the 2 species, especially in North America.
The following lists give biogeographic classifications where Brazilian satintail and cogongrass are known to be present or invasive. In Puerto Rico, cogongrass occurs in early seral bracatinga Mimosa scabrella forests.
Grass Manual on the Web provides distributional maps of Brazilian satintail and cogongrass. However, Shilling and others [ ] found consistent flowering in 11 Florida cogongrass populations, none of which were disturbed. Ro and road construction are important corridors for cogongrass dispersal [ 17].
In Southeast Asia, rhizomes typically occur 4 to 20 inches cm below ground and form dense, extensive layers. Given the taxonomic status of Imperata in North America, information included in this review may apply to both species; however, further research is needed to be certain the 2 taxa respond similarly to fire and control treatments.
Leaves are mostly basal and about 5 to 13 mm wide. Cogongrass grows to 3 feet 1 m in height [ 25]. Actual production was higher because some spikelets had shattered prior to data collection [ ]. Cogongrass reproduces from seed, rhizome expansion, and rhizome fragments [ 4386 ]. Cogongrass stand. Studies in central and northern Florida suggested a high degree of genetic variability among cogongrass populations.
Cogongrass seeds may drift 15 miles 20 km in open country [ 64 ]. However, later research showed cogongrass can produce seed prolifically, even after disturbance [ 94].