Taxonomic name: Cenchrus polystachios (L.) Morrone
Synonyms: Cenchrus setosus Sw. 1788, Gymnotrix geniculata Schult. 1824, Panicum barbatum Roxb. 1820, Panicum cauda-ratti Schumach. 1827, Panicum cenchroides Rich. 1792, Panicum densispicum Poir. 1816, Panicum erubescens Willd. 1809, Panicum polystachion L. 1759, Panicum subangustum Schumach., Panicum triticoides Poir. 1816, Pennisetum alopecuroides Desv. ex Ham. 1825, Pennisetum atrichum Stapf & C.E.Hubb. 1933, Pennisetum borbonicum Kunth 1830, Pennisetum cauda-ratti (Schumach.) Franch. 1895, Pennisetum elegans Nees ex Steud. 1854, Pennisetum erubescens (Willd.) Link 1827, Pennisetum flavescens J.Presl 1830, Pennisetum gabonense Franch. 1895, Pennisetum gracile Benth. 1849, Pennisetum hamiltonii Steud. 1841, Pennisetum hirsutum Nees 1829, Pennisetum indicum Murray var. purpurascens (Kunth) Kuntze 1891, Pennisetum nicaraguense E.Fourn. 1880, Pennisetum pallidum Nees 1829, Pennisetum polystachion (L.) Schult. subsp. setosum (Sw.) Brunken 1979, Pennisetum polystachion (L.) Schult. subsp. atrichum (Stapf & C.E.Hubb.) Brunken 1979, Pennisetum purpurascens Kunth 1816 , Pennisetum reversum Hack. ex Buettner var. gymnochaetium Hack. 1901, Pennisetum reversum Hack. ex Buettner 1890, Pennisetum richardii Kunth 1829, Pennisetum setosum (Sw.) L. Rich., Pennisetum setosum (Sw.) Rich. 1805, Pennisetum sieberi Kunth 1829, Pennisetum stenostachyum Peter 1930, Pennisetum subangustum (Schumach.) Stapf & C.E.Hubb. 1933, Pennisetum tenuispiculatum Steud. 1854, Pennisetum uniflorum Kunth 1816 , Setaria cenchroides (Rich.) Roem. & Schult. 1817, Setaria erubescens (Willd.) P.Beauv. 1812
Common names: dipw rais (Pohnpei), feathery pennisetum (English), mechen katu (Chuuk), missiongrass (English), o tamata (Fiji), pwokso (Pohnpei), queue de chat (French), thin napier grass (English), West Indian pennisetum (English)
Organism type: grass
Cenchrus polystachios (Pennisetum polystachion) is a large grass species originating from Africa and India. It has spread to many Pacific islands and thrives in tropical climates. C. polystachios causes major problems in the Northern Territory of Australia, where it has greatly increased the amount of flammable material in the wooded savanna ecosystem, leading to greater devastation from bushfires.
Tufted annual or perennial grass; culms slender to moderately stout, up to 2m tall, usually 1-2m, simple or few-branched; blades 5-40cm long, 5-18mm wide, glabrous or pubescent; spike dense, yellow brown, 5-25cm long, 13-26mm wide; spikelets purple tinge, yellow-brown, surrounded by bristles, these densely hairy at base, unequal, one longer than the others but not greatly exceeding the next one or two shorter ones, 12-25mm long; spikelets 2-flowered c. 5mm long, upper floret perfect.
Judziewicz (1990) states that C. polystachios is perennial in the new world but annual in the old world.
Pennisetum pedicellatum, Pennisetum purpureum
range/grasslands, ruderal/disturbed, scrub/shrublands
Disturbed, mostly dry, lowland areas and cultivated fields up to 2100m elevation. Dominates dry hillsides in Guam and Fiji. Rarely extend beyond latitudes 23°N and 23°S.
Can act as a host for maize streak virus. Competes with native plant species. Alters the fire regime in areas of northern Australia, increasing the effect of bushfires. Has the potential to be a seed contaminant.
Originally introduced to many areas as a pasture or fodder grass for livestock.
Cenchrus polystachios is also referred to as Pennisetum polystachion
Native range: Tropical Africa to India. Whistler (1995) lists it as native to Central America, which is possibly erroneous.
Known introduced range: Most Pacific island groups, excluding Samoa and Tonga. Australia, Thailand, China, Philippines, Indonesia.
Introduction pathways to new locations
Acclimatisation societies: Introduced as a pasture grass for cattle.
Agriculture: Introduced as a pasture grass for cattle.
Road vehicles (long distance): Seeds have been found transported on cars.
Local dispersal methods
On animals: Bristles on seed heads allow dispersal of seeds through attachment to the coats of animals.
On animals (local): Seeds are able to be wind-dispersed.
Road vehicles: Contractors involved in hay-making and transportation are thought to contribute to the spread of this species in Australia.
Translocation of machinery/equipment (local): Contractors involved in hay-making and transportation are thought to contribute to the spread of this species in Australia.
Transportation of habitat material (local): Contractors involved in hay-making and transportation are thought to contribute to the spread of this species in Australia.
Water currents: Flooding can distribute seeds.
Preventative measures: A Risk assessment of Cenchrus polystachios (Pennisetum polystachion) for Australia was prepared by Pacific Island Ecosystems at Risk (PIER) using the Australian risk assessment system (Pheloung, 1995). The result is a score of 11 and a recommendation of: reject the plant for import (Australia) or species likely to be a pest (Pacific).
Chemical: Herbicides such as ametryn, paraquat, glufosinate ammonium, imazapyr and glyphosate isopropylamine have proved effective at preventing seed germination. Trials have shown that spraying with glyphosate and wetting agents during the plant's maximum growth phase is effective.
Seeds dispersed by wind, flowing water, or sticking to clothing. Can also reproduce through cuttings.
Reviewed by: Colin G. Wilson
Wildlife Management Officer
Department of Infrastructure, Planning and Environment
Parks & Wildlife Service
Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Thursday, 23 March 2006