Paspalum distichum (knotgrass)
Index
- Pictures
- Identity
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Plant Type
- Distribution
- Distribution Table
- History of Introduction and Spread
- Introductions
- Risk of Introduction
- Habitat
- Habitat List
- Host Plants and Other Plants Affected
- Growth Stages
- Biology and Ecology
- Climate
- Air Temperature
- Rainfall Regime
- Soil Tolerances
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Plant Trade
- Impact Summary
- Economic Impact
- Environmental Impact
- Social Impact
- Risk and Impact Factors
- Uses
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- References
- Links to Websites
- Contributors
- Distribution Maps
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Top of pagePreferred Scientific Name
- Paspalum distichum L. 1759
Preferred Common Name
- knotgrass
Other Scientific Names
- Digitaria paspalodes Michx. (1803)
- Panicum paspalodes Michx. (1803)
- Paspalum paspalodes
- Paspalum paspaloides (Michx.) Scribn. 1894
- Paspalum paucispicatum Vasey (1893)
International Common Names
- English: couch paspalum; dallisgrass; devil's grass; ditch-grass; eternity grass; ginger grass; jointgrass; mercer grass; seashore paspalum; seaside millet; silt grass; thompsongrass; victoria grass; water couch; wiregrass
- Spanish: alcanache; camalote saladillo; capim-arame; chepica; grama colorado; grama de agua; grama-braba; gramilla blanca; gramilla dulce; pasto dulce
- French: paspale a deux epis
- Chinese: Hong-ban-gen-cao; liang er cao; shuang sui que bai
- Portuguese: alcanache; graminhão
Local Common Names
- Brazil: capim-pancuan; grama-de-forquilha; grama-doce; pancuam
- Cuba: rapiente
- Germany: Knotgras
- Indonesia: lamhani
- Iraq: shalhaw
- Italy: gramignone d'acqua; panico aquatico; paspalo distico
- Japan: Chikugo-suzumenohie; Kishu-suzume-no-hie
- Nepal: ghunde banso
- Portugal: grama de Joanopolis
- South Africa: bankrotkweek; kweekpaspalum
EPPO code
- PASDS (Paspalum distichum)
Summary of Invasiveness
Top of pageP. distichum is a fast-growing rhizomatous grass of wet areas. It has become a major weed of rice and many other crops, as well as occurring in uncropped wetlands in both its native and introduced regions. Its introduction to Europe, Asia and the Pacific is not well documented but apparently occurred many years ago. New records are reported in e.g. Indonesia, Spain and Croatia, suggesting that it continues to spread in countries to which it has been introduced.
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Monocotyledonae
- Order: Cyperales
- Family: Poaceae
- Genus: Paspalum
- Species: Paspalum distichum
Notes on Taxonomy and Nomenclature
Top of pageBoth P. distichum and P. paspalodes are accepted names for this weed. The use of the Linnaean name ‘P. distichum’ was challenged by Renvoize and Clayton (1980) as they considered he had applied the name to a specimen of P. vaginatum on the same original herbarium sheet. This was in turn challenged by Guedes (1981) and after further deliberation by the International Association for Plant Taxonomy (IAPT) the original challenge was disallowed (Brummitt, 1983). Hence the original, more popular name P. distichum is retained for this data sheet, though P. paspalodes is still used by a number of authorities including Flora Europaea (Royal Botanic Garden Edinburgh, 2009).
There has been corresponding uncertainty over the spelling of the main synonym – ‘paspalodes’ often appearing as ‘paspaloides.’ In 1894, Scribner published the new combination ‘Paspalum paspaloides’, based on the earlier name Digitaria paspalodes Michx. 1803, but taking the liberty of ‘correcting’ the spelling from ‘paspalodes’ to ‘paspaloides’. However, this correction is not allowed under the rules of nomenclature. Hence, the use of the spelling ‘paspaloides’, although widespread, is not strictly correct (Henry Noltie, personal communication). FAO (2009) still uses ‘P. paspaloides’ for P. distichum as defined here (and ‘P. distichum’ for what is normally referred to as P. vaginatum).
A number of synonyms have been listed in the Identity section, but there are a great many more quoted by e.g. Bor (1960) and by Missouri Botanic Garden (2009).
The use of the name ‘P. distichum’ by Renvoize and Clayton for the closely related P. vaginatum, together with some understandable confusion in field identification means that there are inevitably some records of P. distichum in this data sheet which may more correctly be P. vaginatum.
A range of varieties have been named. In Japan and Korea, var. indutum is distinguished from the typical form and does show some differences in ecology etc. Most recently in France, P. distichum var. paucispicatum has been described, corresponding to Mexican material described originally as P. paucispicatum (Verloove and Reynders, 2007). A mutant type, ‘Flexi-green’, has been registered as a turf grass in Australia.
There is also plenty of confusion with regard to the popular names used; dallisgrass is applied to both P. distichum and P. dilalatum; knotgrass is the officially recognised common name in the USA, but in the UK this applies to the unrelated Polygonum aviculare.
Description
Top of pageThe morphology of P. distichum has been described in detail by Chase (1929). It is a widely creeping perennial with slender rhizomes, extensively stoloniferous, often forming loose mats. The stolons are usually slender, subcompressed, sometimes as much as one metre long. On average, the sheaths are less loose than in Paspalum vaginatum, the blades are usually well developed; the branches are erect or ascending, most of them finally flowering, 6-50 cm tall, often sparingly branching. The culms are subcompressed, the nodes dark, often with a few ascending hairs; the sheaths are loose, keeled, and commonly pilose on the margins toward the summit. The ligule is membranaceous, about 0.5 mm long; the blades are flat, ascending, 3-12 cm long, and 2-6 mm wide at the rounded, ciliate base, tapering to an acuminate, sometimes involute apex; they are dull green, relatively soft in texture, and occasionally minutely pubescent on the upper surface. The peduncles are commonly short, often included; there are usually two racemes, rarely as many as four, from erect to reflexed, commonly incurved, 1.5-7 cm long, rarely longer. The rachis is slightly pedunculate in one, sometimes both racemes, usually with a few white hairs in the axil, 1-1.5 mm, rarely 2 mm wide, triangular, and minutely scabrous on the margin. The spikelets are solitary (rarely in pairs in the middle of the raceme), imbricate, 2.5-3 mm wide (size variation is sometimes found in the same plant), elliptic, abruptly acute, and pale green. The first glume is frequently developed; the second glume and sterile lemma are equal, with three to five veins, the midrib is relatively prominent. The glume is minutely appressed-pubescent, sometimes obscurely so. The fruit is 2.5-2.8 mm long, about 1.2 mm wide, and elliptic. Pollen morphology has been described by Ma GuoHua et al. (2001).
P. distichum is unusual in the variability in size of the lower glume: even within a single raceme it can vary from absent to conspicuous, up to half the length of the spikelet.
P. distichum exhibits considerable variability, thought to result from both the heteroploidy shown by the species, and the existence of genetic differences among individuals of the same cytotype (Echarte et al., 1992).
Distribution
Top of pageP. distichum has almost world-wide distribution in tropical and subtropical regions where temperature and moisture conditions favour its C4 growth habit. Distribution is throughout North America, except Canada; Mexico, Central America, and all of South America; southern Europe; southern former USSR; the Middle East; the Indian subcontinent; South-East Asia; China; Japan; Korea Republic and Korea Democratic People's Republic; the Philippines; Australia; New Zealand; and the Pacific Islands. It occurs in southern and North Africa, but not in East, West or Central Africa.
It is far from clear just where P. paspalum is truly native. It is generally accepted that it is native in N. and S. America and introduced to Europe and most of Asia. PIER (2009) suggests that it is native in the Pacific area, though introduced to Hawaii, Australia and New Zealand. Other sources suggest it could also be native in southern Africa and in Australia.
Distribution Table
Top of pageThe distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Last updated: 12 May 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
|||||||
Algeria | Present | Introduced | Original citation: Le (1991) | ||||
Egypt | Present | Introduced | |||||
Eswatini | Present | Introduced | Invasive | ||||
Lesotho | Present | ||||||
Libya | Present | Introduced | Original citation: Le (1991) | ||||
Madagascar | Present | Introduced | |||||
Mauritius | Present | Introduced | |||||
Morocco | Present | Introduced | |||||
Seychelles | Present | Introduced | Agalega Island (PIER, 2009) | ||||
South Africa | Present | Introduced | |||||
Tunisia | Present | ||||||
Zimbabwe | Present | Introduced | 1960 | ||||
Asia |
|||||||
Azerbaijan | Present | ||||||
Bangladesh | Present, Widespread | Introduced | Invasive | ||||
Bhutan | Present, Widespread | Introduced | |||||
Brunei | Present | Introduced | |||||
Cambodia | Present | Introduced | |||||
China | Present, Widespread | Introduced | |||||
-Anhui | Present | Introduced | |||||
-Fujian | Present | Introduced | |||||
-Guangdong | Present, Widespread | Introduced | |||||
-Guangxi | Present, Widespread | Introduced | |||||
-Guizhou | Present | ||||||
-Hainan | Present | Introduced | |||||
-Henan | Present | Introduced | |||||
-Hubei | Present, Widespread | ||||||
-Hunan | Present | Introduced | |||||
-Jiangsu | Present, Widespread | Introduced | |||||
-Shandong | Present | Introduced | |||||
-Sichuan | Present | Introduced | |||||
-Yunnan | Present, Widespread | ||||||
-Zhejiang | Present | Introduced | |||||
Cocos Islands | Present | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Hong Kong | Present | Introduced | |||||
India | Present | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
-Andaman and Nicobar Islands | Present | Introduced | |||||
-Assam | Present | Introduced | |||||
-Bihar | Present | Introduced | |||||
-Delhi | Present | Introduced | |||||
-Haryana | Present | Introduced | |||||
-Himachal Pradesh | Present | Introduced | |||||
-Jammu and Kashmir | Present | Introduced | |||||
-Kerala | Present | ||||||
-Madhya Pradesh | Present | Introduced | |||||
-Maharashtra | Present | Introduced | |||||
-Manipur | Present | Introduced | |||||
-Meghalaya | Present | Introduced | |||||
-Nagaland | Present | Introduced | |||||
-Odisha | Present | Introduced | |||||
-Punjab | Present | ||||||
-Rajasthan | Present | Introduced | |||||
-Sikkim | Present | Introduced | |||||
-Tamil Nadu | Present | Introduced | |||||
-Uttar Pradesh | Present | Introduced | |||||
-West Bengal | Present | Introduced | |||||
Indonesia | Present, Widespread | Introduced | |||||
-Java | Present, Widespread | Introduced | Invasive | Only recently noticed on Java in 1979; First reported: 1970s | |||
Iran | Present | Introduced | Invasive | ||||
Iraq | Present, Widespread | Introduced | |||||
Israel | Present, Widespread | Introduced | |||||
Japan | Present | Introduced | Invasive | ||||
-Kyushu | Present, Widespread | Introduced | Invasive | ||||
-Ryukyu Islands | Present | Introduced | |||||
Laos | Present | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Lebanon | Present | ||||||
Malaysia | Present | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Myanmar | Present | Introduced | |||||
Nepal | Present | Introduced | |||||
Pakistan | Present | Introduced | Invasive | ||||
Philippines | Present, Widespread | Introduced | Invasive | ||||
Saudi Arabia | Present | ||||||
South Korea | Present | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Sri Lanka | Present | Introduced | |||||
Syria | Present | ||||||
Taiwan | Present, Widespread | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Thailand | Present | Introduced | |||||
Turkey | Present | Introduced | |||||
Vietnam | Present | Introduced | |||||
Europe |
|||||||
Albania | Present | Introduced | 1959 | As: Paspalum paspalodes | |||
Austria | Present | Introduced | 1945 | ||||
Belgium | Present | Introduced | 1950 | ||||
Bosnia and Herzegovina | Present | Introduced | 1954 | As: Paspalum paspalodes | |||
Bulgaria | Present | Introduced | 1959 | ||||
Croatia | Present | Introduced | |||||
France | Present, Localized | Introduced | |||||
-Corsica | Present | Introduced | 1928 | ||||
Greece | Present | Introduced | Invasive | ||||
Italy | Present | Introduced | |||||
Malta | Present | ||||||
Portugal | Present, Widespread | Introduced | Invasive | ||||
-Azores | Present | Introduced | 1857 | ||||
-Madeira | Present | Introduced | 1894 | ||||
Romania | Present | Introduced | 1992 | ||||
Russia | Present | Original citation: Häfliger and Scholz (1980) | |||||
-Central Russia | Present | Introduced | |||||
-Russia (Europe) | Present | ||||||
-Russian Far East | Present | Original citation: Häfliger and Scholz (1980) | |||||
-Southern Russia | Present | Invasive | |||||
Slovenia | Present, Localized | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Spain | Present | Introduced | 1824 | ||||
-Canary Islands | Present | Introduced | As: Paspalum paspalodes. First reported: 1940's | ||||
Ukraine | Present | ||||||
United Kingdom | Present, Localized | Introduced | |||||
North America |
|||||||
Antigua and Barbuda | Present | Native | |||||
Bahamas | Present | Native | |||||
Belize | Present | Native | |||||
Bermuda | Present | Native | |||||
Costa Rica | Present | Native | |||||
Cuba | Present, Widespread | Native | |||||
Dominica | Present | Native | Original citation: Häfliger and Scholz (1980) | ||||
Dominican Republic | Present | Native | |||||
El Salvador | Present | Native | Original citation: Häfliger and Scholz (1980) | ||||
Guadeloupe | Present | ||||||
Guatemala | Present | Native | |||||
Haiti | Present | Native | |||||
Honduras | Present | ||||||
Jamaica | Present | Native | |||||
Martinique | Present | Native | |||||
Mexico | Present | Native | Original citation: Häfliger and Scholz (1980) | ||||
Nicaragua | Present | Native | |||||
Panama | Present | Native | Original citation: Häfliger and Scholz (1980) | ||||
Puerto Rico | Present | Native | |||||
Saint Lucia | Present | Native | |||||
Saint Vincent and the Grenadines | Present | Native | |||||
Trinidad and Tobago | Present | Native | |||||
U.S. Virgin Islands | Present | Native | |||||
United States | Present | Native | |||||
-Alabama | Present | Native | |||||
-Arizona | Present | Native | |||||
-Arkansas | Present | Native | |||||
-California | Present | Native | |||||
-Florida | Present | Native | |||||
-Georgia | Present | Native | |||||
-Hawaii | Present | Introduced | Invasive | Kaua'l O'aha Islands (PIER, 2009) | |||
-Idaho | Present | Native | |||||
-Kansas | Present | Native | |||||
-Kentucky | Present | Native | |||||
-Louisiana | Present | ||||||
-Maryland | Present | Native | |||||
-Mississippi | Present | Native | |||||
-Missouri | Present | Native | |||||
-Nevada | Present | Native | |||||
-New Jersey | Present | ||||||
-New Mexico | Present | ||||||
-North Carolina | Present | ||||||
-Oklahoma | Present | Native | |||||
-Oregon | Present | Native | |||||
-Pennsylvania | Present | Native | |||||
-South Carolina | Present | Native | |||||
-Tennessee | Present | Native | |||||
-Texas | Present | Native | |||||
-Utah | Present | Native | |||||
-Virginia | Present | ||||||
-Washington | Present | Native | |||||
Oceania |
|||||||
Australia | Present | Original citation: Häfliger and Scholz (1980) | |||||
-Lord Howe Island | Present | Introduced | 1898 | As: Paspalum paspalodes | |||
-New South Wales | Present, Widespread | Introduced | Original citation: PlantNet (2009) | ||||
-Northern Territory | Present | Introduced | Original citation: PlantNet (2009) | ||||
-Queensland | Present | Introduced | Original citation: PlantNet (2009) | ||||
-South Australia | Present | Introduced | Original citation: PlantNet (2009) | ||||
-Tasmania | Present | Introduced | Original citation: PlantNet (2009) | ||||
-Victoria | Present | Introduced | Original citation: PlantNet (2009) | ||||
-Western Australia | Present | Introduced | Original citation: PlantNet (2009) | ||||
Christmas Island | Present | Introduced | Original citation: Häfliger and Scholz (1980) | ||||
Cook Islands | Present | Original citation: Häfliger and Scholz (1980) | |||||
Federated States of Micronesia | Present | Invasive | Chuuk, Kposrae, Pohnpei and Yap Islands (PIER, 2009) | ||||
Fiji | Present | Original citation: Häfliger and Scholz (1980) | |||||
French Polynesia | Present | Original citation: Häfliger and Scholz (1980) | |||||
Guam | Present | Original citation: Häfliger and Scholz (1980) | |||||
Kiribati | Present | Original citation: Häfliger and Scholz (1980) | |||||
Marshall Islands | Present | Ailinglaplap, Jaluit, Ailuk, Arno and Likiep Islands (PIER, 2009) | |||||
Nauru | Present | Original citation: Häfliger and Scholz (1980) | |||||
New Zealand | Present, Localized | Introduced | Invasive | ||||
Northern Mariana Islands | Present | Anatahan, Pagan, Saipan and Tinian Islands (PIER, 2009) | |||||
Palau | Present | Angaur, Tobi, Babeldaob, Koror, Ngerkebesang and Peleliu Islands (PIER, 2009) | |||||
U.S. Minor Outlying Islands | Present | Original citation: Häfliger and Scholz (1980) | |||||
-Johnston Atoll | Present | Original citation: Häfliger and Scholz (1980) | |||||
-Wake Island | Present | ||||||
South America |
|||||||
Argentina | Present | Native | |||||
Bolivia | Present | Native | |||||
Brazil | Present | Native | |||||
-Alagoas | Present | Native | |||||
-Bahia | Present | Native | |||||
-Ceara | Present | ||||||
-Espirito Santo | Present | Native | |||||
-Goias | Present | Native | |||||
-Mato Grosso do Sul | Present | Native | |||||
-Minas Gerais | Present | Native | |||||
-Para | Present | ||||||
-Parana | Present | Native | |||||
-Pernambuco | Present | Native | |||||
-Rio de Janeiro | Present | Native | |||||
-Rio Grande do Norte | Present | ||||||
-Rio Grande do Sul | Present | Native | |||||
-Santa Catarina | Present | Native | |||||
-Sao Paulo | Present | Native | |||||
-Sergipe | Present | Native | |||||
Chile | Present | Native | Invasive | ||||
Colombia | Present | Native | Invasive | ||||
Ecuador | Present | Native | |||||
French Guiana | Present | ||||||
Guyana | Present | Native | |||||
Paraguay | Present | Native | |||||
Peru | Present | Native | |||||
Suriname | Present | Native | |||||
Uruguay | Present | Native | |||||
Venezuela | Present | Native | Original citation: Häfliger and Scholz (1980) |
History of Introduction and Spread
Top of pageThere are few clear records of the introduction of P. distichum to new territories. There is a firm date for France of 1802 (Le Floc’h, 1991). In Portugal it was first reported in 1887 (Aguiar et al., 2005). In Java, Indonesia, Everaats (1981) indicates that it was relatively newly known at that time. Likewise in Iran in 2000 (Hamzeh'ee, 2000). In Spain it has only recently moved into the province of Léon (Egido Mazuelas et al., 2007). In Croatia it is also infesting new areas (Milovoic, 2001).
Introductions
Top of pageIntroduced to | Introduced from | Year | Reason | Introduced by | Established in wild through | References | Notes | |
---|---|---|---|---|---|---|---|---|
Natural reproduction | Continuous restocking | |||||||
France | 1802 | Forage (pathway cause) | Yes | Floc'h (1991); Floc'h E le (1991); Le (1991) | ||||
Java | 1970s | Yes | Everaarts (1981) | |||||
Portugal | 1887 | Yes | Aguiar et al. (2005) |
Risk of Introduction
Top of pageThere are highly significant risks of further spread of P. distichum into regions not already infested – especially northern sub-sahelian Africa, which has so far escaped invasion. The conditions, especially in West Africa are likely to be very favourable and the risks to the important rice growing areas there and in East Africa are high. Although spreading mainly vegatatively once established, P. distichum does produce abundant fertile seed which could be transferred as a contaminant of other crop seeds, or in hay or forage. As P. distichum has shown useful characteristics as an aid to soil conservation or as a livestock feed, there could be misguided deliberate introduction.
Habitat
Top of pageAccording to Häfliger and Scholz (1980)P. distichum is found in wasteland areas, rotation crops, perennial crops and aquatic habitats, but not too frequently on grassland.
P. distichum is a non-submerged aquatic plant commonly occurring in streams and alluvial flatlands in the tropics and subtropics, and throughout the world. It populates still or moving water to a depth of one metre or more; it may also be a problem in merely irrigated conditions. It is a C4 plant (Mesleard et al., 1993) adapted to semi-aquatic environments (Datta et al., 1979) and is not cold tolerant.
P. distichum has the capacity to bind soil in streams which are subject to erosion in the tropics, and provides grazing in flat coastal regions and stream beds. It is a valuable pasture grass on alluvial flats (Chase, 1929; Bor, 1960). Attempts have been made to select strains with high palatability and limited regenerative capacity (Ikeda et al., 1988). P. distichum has a capacity for explosive growth which restricts its use for binding soil in intensively cultivated areas (Li, 1981). The weed spreads readily by seed and vegetative reproduction, by its numerous stolons and rhizomes, to become a persistent weed (Smiley, 1922; Wilkinson and Jacques, 1979; Huang et al., 1987). The percentage of hemicryptophytes in the ruderal (riverbank) environments of North Africa is increasing and becoming a significant problem (Le-Floc'h, 1991).
P. distichum occurs in ditches and wet, but rarely brackish, areas as far north as Washington, USA, and as far south as Argentina and Chile; also on temperate coasts of the Eastern Hemisphere. Most references to this species occurring in saline coastal areas are attributable to confusion with P. vaginatum, but Leithead et al. (1971) describe both species and comment that P. distichum ‘grows primarily on fresh water marshes and occasionally on brackish marshes. Tolerates moderate salinity and standing water’. It is a serious weed in areas where irrigated crops such as rice or cotton are the main crops in rotation. Thus, it is an important weed in the natural floodplains and wetlands in India, and in the paddy fields of Japan, China and the Philippines. However, it can proliferate in drier conditions provided abundant water is present for at least part of the growth cycle. It can infest orchards, asparagus plantings, or vineyards which are irrigated. It is found in highland pastures in Thailand in years of heavy rainfall, but is considered as a tropical lowland pest in this region (Falvey and Hengmichai, 1978; Datta et al., 1979). The plant is predominantly lowland, rarely found at altitudes greater than 300 m (Robbins et al., 1951; Townsend et al., 1968). In Europe it has come to dominate riparian and wet alluvial plains in Portugal (Bernez et al., 2005) and in Greece (Stroh, 2006).
Habitat List
Top of pageCategory | Sub-Category | Habitat | Presence | Status |
---|---|---|---|---|
Terrestrial | ||||
Terrestrial | Managed | Cultivated / agricultural land | Principal habitat | Harmful (pest or invasive) |
Terrestrial | Managed | Managed forests, plantations and orchards | Secondary/tolerated habitat | Harmful (pest or invasive) |
Terrestrial | Managed | Managed grasslands (grazing systems) | Secondary/tolerated habitat | Productive/non-natural |
Terrestrial | Managed | Disturbed areas | Secondary/tolerated habitat | Natural |
Terrestrial | Managed | Rail / roadsides | Secondary/tolerated habitat | Natural |
Terrestrial | Managed | Urban / peri-urban areas | Secondary/tolerated habitat | Natural |
Terrestrial | Natural / Semi-natural | Natural grasslands | Secondary/tolerated habitat | Natural |
Terrestrial | Natural / Semi-natural | Riverbanks | Secondary/tolerated habitat | Natural |
Terrestrial | Natural / Semi-natural | Wetlands | Principal habitat | Natural |
Littoral | Coastal areas | Secondary/tolerated habitat | Natural | |
Freshwater | Irrigation channels | Principal habitat | Harmful (pest or invasive) | |
Freshwater | Irrigation channels | Principal habitat | Natural | |
Freshwater | Lakes | Secondary/tolerated habitat | Natural | |
Freshwater | Reservoirs | Secondary/tolerated habitat | Natural | |
Freshwater | Rivers / streams | Secondary/tolerated habitat | Harmful (pest or invasive) | |
Freshwater | Rivers / streams | Secondary/tolerated habitat | Natural | |
Freshwater | Ponds | Secondary/tolerated habitat | Harmful (pest or invasive) | |
Freshwater | Ponds | Secondary/tolerated habitat | Natural | |
Brackish | Estuaries | Secondary/tolerated habitat | Natural |
Host Plants and Other Plants Affected
Top of pagePlant name | Family | Context | References |
---|---|---|---|
Allium porrum (leek) | Liliaceae | Other | |
Asparagus officinalis (asparagus) | Liliaceae | Main | |
Brassica juncea var. juncea (Indian mustard) | Brassicaceae | Other | |
Citrus | Rutaceae | Main | |
Corchorus capsularis (white jute) | Tiliaceae | Other | |
Curcuma longa (turmeric) | Zingiberaceae | Other | |
fruits | Main | ||
Gossypium (cotton) | Malvaceae | Main | |
Gossypium hirsutum (Bourbon cotton) | Malvaceae | Main | |
Oryza sativa (rice) | Poaceae | Main | |
pastures | Main | ||
Phaseolus vulgaris (common bean) | Fabaceae | Other | |
Triticum (wheat) | Poaceae | Other | |
Vitis vinifera (grapevine) | Vitaceae | Main | |
Zea mays (maize) | Poaceae | Other |
Growth Stages
Top of pageBiology and Ecology
Top of pageGenetics
Hexaploid (2n=60) and tetraploid (2n=40) populations are common (Kadono, 1985; Shibayama, 1988; Echarte et al., 1992), and Echarte et al. (1992) have documented the existence of pentaploids (2n=50) and several hyperpentaploids (2n=52, 54, 57 and 58) in Argentina. Bor (1960) also records 2n=48.
P. distichum exhibits considerable variability, thought to result from both the heteroploidy shown by the species, and the existence of genetic differences among individuals of the same cytotype (Echarte et al., 1992).
Reproductive Biology
P. distichum has a high capacity for asexual reproduction. Under suitable conditions, almost every node of the aerial shoots (stolons) and rhizomes are capable of rooting and producing new plants. Under optimum conditions, P. distichum can elongate at a rate of 15-20 cm per week (Noda and Obayashi, 1971). Okuma et al. (1983) reported that within 2-3 years of planting overwintering stems of P. distichum on the bank of a stream, the entire surface of the stream was covered with a floating mat of the weed.
The weed also produces many seeds. Seed production by P. distichum has been estimated at 100 seeds per panicle and was about 100,000/m² in a river studied by Okuma and Chikura (1984). About 5-10% of the seeds produced were viable and the maximum, minimum and optimum temperatures for seed germination were 40, 20 and 30°C, respectively. Even at the optimum incubation temperature, 60% of viable seeds remained dormant. Exposure of seeds to 16-h daylength at optimum temperatures of 28-35°C increased germination from 14 to 40% (Huang and Hsiao, 1987). Pre-chilling seeds at 6°C and a 2-h heat treatment at 40°C had no effect on germination, and treatment with gibberellic acid (GA3) had little effect. Treatment of the seeds with oxidants including sodium hypochlorite, hydrogen peroxide and concentrated sulphuric acid indicated that seed dormancy was imposed mainly by seed coverings, including the hull and seed coat membranes. Seeds play an important role in the winter survival of P. distichum in regions where temperatures approach the critical limit for the species (Shibayama, 1988).
In Argentina, Echarte et al. (1992) confirmed that P. distichum is an out-crossing species, though in China Ma GuoHua et al. (2003) concluded that the tetraploid P. distichum could be considered to be a facultative apomict reproducing by apospory. Quarín and Burson (1991) likewise concluded that it reproduces by aposporous apomixis and Srivastava and Purnima (1990) refer to it as an obligate asporous apomict with only aposporous embryo sacs. Seeds mature 20-30 days after flower emergence (Manuel et al., 1979).
Physiology and Phenology
Single node segments of P. distichum sprout faster from stems than from rhizomes, and the rooting of shoots on contact with the soil stimulates new shoot production (Manuel and Mercado, 1977). Stolons root readily at the nodes, and elongation rates of up to 15-20 cm per week have been observed at high temperatures (Noda and Obayashi, 1971). On average, the maximum, optimum and minimum temperatures for sprouting and rooting of P. distichum segments are 40, 30-35 and 10°C, respectively (Huang et al., 1987). Shoots of P. distichum collected in different seasons differed in their sprouting and rooting responses at different incubation temperatures, providing a possible survival mechanism for the species. The rate of sprouting, rooting and the early growth of both single-node shoot and rhizome segments increased with incubation temperature up to 30°C, and then declined at 40°C. Growth was poor at 10°C. Single-node stem segments sprouted faster in a 16-h light regime than in darkness. Rooting was optimum in the dark at low temperatures; and in the light at high temperatures. Stems of P. distichum are kept in reserve by apical and bud dominance, to replace those destroyed under adverse conditions; a further survival mechanism for this species. Water, nutrient and light levels which favour photosynthesis and reduced transpiration are favourable to axillary bud growth (Liu et al., 1991).
P. distichum flourishes at high temperatures and is tolerant of high moisture conditions (Mesléard et al., 1993), as is characteristic of many C4 species.
Environmental Requirements
P. distichum is quite sensitive to shade. Plants kept at short daylengths (8 h) have smaller leaves and internodes than those kept at longer daylengths which tend to prolong maturation; plants in all treatments flower in 14-16 days. Deep (10-15 cm) water levels delay flowering.
Response to climatic conditions in New Zealand has been studied by Campbell et al. (1999). As a C4 plant it showed less tolerance to cold conditions than C3 species.
P. distichum flourishes in wet soils but these are generally aerobic rather than anaerobic (Green and Brock, 1994). Tolerance of salinity is somewhat uncertain. There are many references to the occurrence of the weed in coastal areas, but possible confusion with the salt-tolerant P. vaginatum makes many of these references unreliable. Leithead et al. (1971) do however describe both species and comment that P. distichum ‘grows primarily on fresh water marshes and occasionally on brackish marshes. Tolerates moderate salinity and standing water’.
Climate
Top of pageClimate | Status | Description | Remark |
---|---|---|---|
Af - Tropical rainforest climate | Tolerated | > 60mm precipitation per month | |
Am - Tropical monsoon climate | Preferred | Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25])) | |
As - Tropical savanna climate with dry summer | Tolerated | < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25]) | |
Aw - Tropical wet and dry savanna climate | Tolerated | < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25]) | |
Cf - Warm temperate climate, wet all year | Preferred | Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year | |
Cs - Warm temperate climate with dry summer | Preferred | Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers | |
Cw - Warm temperate climate with dry winter | Tolerated | Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters) |
Air Temperature
Top of pageParameter | Lower limit | Upper limit |
---|---|---|
Mean annual temperature (ºC) | 5 | 25 |
Mean maximum temperature of hottest month (ºC) | 35 | |
Mean minimum temperature of coldest month (ºC) | -3 |
Soil Tolerances
Top of pageSoil drainage
- free
- impeded
- seasonally waterlogged
Soil reaction
- acid
- alkaline
- neutral
Soil texture
- heavy
- light
- medium
Special soil tolerances
- saline
Notes on Natural Enemies
Top of pageRelatively few natural enemies have been recorded for P. distichum and none have been proposed as potential biocontrol agents. The most significant natural enemy is the ergot fungus Claviceps paspali, infection with which can lead to serious toxicity to livestock.
Means of Movement and Dispersal
Top of pageNatural Dispersal (Non-Biotic)
Natural dispersal must inevitably occur by movement of seeds in water.
Vector Transmission (Biotic)
Local movement may occur on or in livestock but is not documented.
Accidental Introduction
Accidental introduction is likely to occur in hay or as seed contamination of other crop seeds but is not documented.
Intentional Introduction
Most of the spread around the world has presumably occurred as a result of deliberate introduction of the species as a pasture grass, but there are few available records.
Pathway Causes
Top of pageCause | Notes | Long Distance | Local | References |
---|---|---|---|---|
Animal production | Yes | Yes | ||
Crop production | Yes | Yes |
Plant Trade
Top of pagePlant parts liable to carry the pest in trade/transport | Pest stages | Borne internally | Borne externally | Visibility of pest or symptoms |
---|---|---|---|---|
Bulbs/Tubers/Corms/Rhizomes | ||||
True seeds (inc. grain) |
Impact Summary
Top of pageCategory | Impact |
---|---|
Cultural/amenity | Positive and negative |
Economic/livelihood | Negative |
Environment (generally) | Positive and negative |
Economic Impact
Top of page
Economic impact occurs primarily in rice, where the weed can become dominant, causing loss of crop yield and/or increased costs of control, whether manually or by herbicides. As listed by Holm et al. (1979) it occurs as a ‘serious’ weed in Australia, Chile, Guyana, Iraq, Israel, Pakistan, Portugal, the former USSR, and Spain and as a ‘principal’ weed in Colombia, France, Iran, New Zealand and Swaziland. It is especially serious in Portugal, where surveys have shown the weed to be present in over 80% of rice fields (Vasconcelos et al., 1998). It is recorded as a major weed in Phaseolus vulgaris in Egypt (Hussein, 2003); in wheat in Bangladesh (Alam et al., 1997); and in asparagus in Chile and New Zealand.
P. distichum is a serious weed in irrigated crops, and irrigation ditches are particularly subject to invasion. Seasonal flooding in some locations, and enriched nitrogen along riverbeds favours its spread. Herbicides must be used with caution in paddy fields and irrigated areas. The weed is resistant to many herbicides, and its potential for vegetative reproduction makes it difficult to control even with intensive cultivation. No natural enemies suitable for biological control have yet been identified. The most effective control methods, involving intensive ground preparation and appropriate herbicide applications, are expensive. Low-till or no-till agricultural practices, which reduce labour costs, are not practical as crop losses can be as high as 75-80% in the presence of P. distichum. The major economic impact of P. distichum is the input of labour required for adequate control.
Although P. distichum is often grown and/or exploited as feed for livestock, there are reports from South Africa, France, Albania and Japan of poisoning resulting from infection of the seedheads by Claviceps paspali, causing ergotism.
Environmental Impact
Top of pageIn India, Keoladeo National Park has been seriously invaded by P. distichum, to the detriment of the native vegetation (Middleton, 1998). Invasion of natural wetlands by P. distichum is also serious in Portugal, where it is considered a threat for particular river flora and consequently for the integrity of the river system (Bernez et al., 2005), and also in Greece (Stroh, 2006).
Dominance of P. distichum in natural wetlands or waterways can also result in reduced fish populations (Kumar and Mittal, 1993).
Social Impact
Top of pageDense growth of P. distichum can greatly increase mosquito populations compared with more open vegetation, hence decreasing amenity and increasing risk of disease (Lawler et al., 2007).
P. distichum is noted as a weed of ornamental turf in China (Zhou Qiang et al., 2004), and in France (Bourgoin and Guérin, 1999).
Risk and Impact Factors
Top of page- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Pioneering in disturbed areas
- Long lived
- Fast growing
- Has high reproductive potential
- Gregarious
- Has propagules that can remain viable for more than one year
- Reproduces asexually
- Has high genetic variability
- Ecosystem change/ habitat alteration
- Host damage
- Modification of hydrology
- Modification of nutrient regime
- Modification of successional patterns
- Monoculture formation
- Negatively impacts agriculture
- Negatively impacts animal health
- Negatively impacts livelihoods
- Reduced amenity values
- Reduced native biodiversity
- Threat to/ loss of native species
- Competition - monopolizing resources
- Filtration
- Poisoning
- Rapid growth
- Highly likely to be transported internationally deliberately
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
- Difficult/costly to control
Uses
Top of pageEconomic Value
P. distichum is not always considered a weed. It is introduced into rice paddy fields as a forage crop by some Japanese farmers (Ikeda et al., 1983). Bor (1960) comments that P. distichum is considered in many parts of the world to be a valuable pasture grass and has been used extensively in areas subject to flooding. ‘P. paspalodes’ was cultivated in the Bordeaux region of France as early as 1802 for use as pasture. While P. distichum survives root flooding and submergence without difficulty, protracted deep flooding can reduce photosynthesis in existing leaves and can be detrimental to growth (Hsiao and Huang, 1989b).
In Japan, ‘roll bale silage’ from P. distichum grown in paddy fields with a large amount of nitrogen fertilizer show a potential in terms of feeding value (Asano et al., 2007).
In Australia, Rosicky et al. (2006) comment that P. distichum is favoured as a highly palatable forage for stock.
Environmental Services
In Australia, Rosicky et al. (2006) comment that P. distichum is highly favoured for its environmental benefits in providing thick mulch cover, and assisting in the revegetation of bare ground. Similarly it is favoured as a ground cover in Florida, USA (Jenkins et al., 2004), while in China, it is tolerant of heavy metals and suitable for revegetation of ground contaminated by lead, zinc and copper (Shu et al., 2002).
P. distichum has been used for purification of water, as in Korea, where it was considered valuable for extracting nitrogen and phosphorus from eutrophic water (Lee et al., 2004) and in Australia for removal of phosphorus (Wen et al., 2002).
Uses List
Top of pageAnimal feed, fodder, forage
- Fodder/animal feed
- Forage
Environmental
- Amenity
- Erosion control or dune stabilization
- Host of pest
- Land reclamation
- Revegetation
- Soil conservation
Similarities to Other Species/Conditions
Top of pageP. distichum is sometimes confused with Paspalum vaginatum but is distinguishable by the slightly more turgid spikelets, a glume and sterile lemma which are not papery, a more pronounced midrib, and a glume which is at least obscurely pubescent (Chase, 1929). P. distichum is also distinguished by the unusually variable size of the lower glume. P. vaginatum is almost always associated with saline or brackish conditions, especially near coasts, but also in saline soils inland (e.g. Arabia), whereas P. distichum does not generally occur under these conditions.
Many other species of Paspalum can occur as weeds. One of the most widespread of these is a complex of closely-related taxa which include P. commersonii and P. orbiculare but which are usually known as P. scrobiculatum (qv). This is widespread in Asia and Africa. It is not likely to be confused with P. distichum as it has a tufted habit whether spreading or erect, annual or perennial, but without runners or rhizomes. The inflorescence also differs in having spikelets almost round in outline.
Prevention and Control
Top of pageDue to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
SPS Measures
P. distichum is listed as an invasive alien plant in Europe (EPPO, 2009), requiring member countries to minimise the risks of introduction, and of spread within their countries.
Control
Cultural control and sanitary measures
Methods used to control P. distichum differ depending on whether the crops in which the weed is growing are produced under flooding or irrigation. Farmers in the Philippines consider P. distichum and Echinochloa spp. to be the most difficult weeds to control (Fajardo and Moody, 1990). Herbicides are expensive and are used sparingly, but acceptable levels of control can be achieved due to the high seeding rates, high fertilizer rates, and the use of integrated cultural practices. Flooding and deep burial inhibit the growth of P. distichum as oxygen is required for sprouting from stem cuttings centering around the joints. No sprouting was observed from severed creeping stems of P. distichum which were buried in puddled soil or submerged in water. Most sprouting occurs from overwintering stems lying above the water; almost none occurs from submerged overwintering stems. Flooding reduces the competitive advantage of P. distichum with respect to rice (Manuel and Mercado, 1977; Manuel et al., 1979). P. distichum is sensitive to shade (Manuel and Mercado, 1977; Manuel et al., 1979; Ito et al., 1987) and higher crop seeding rates, closer distances at transplanting, and the use of taller, more competitive cultivars are, therefore, potential control measures.
The effects of no-tillage systems on weed development in a variety of crops was investigated by Gong and Li (1991). The underground vegetative portions of P. distichum tend to be shallow, with aggressive shoot development. No-tillage systems are not feasible in areas heavily infested with P. distichum and minimum tillage is, at the very least, necessary for satisfactory yields of semi-dwarf rice (Datta et al., 1979; Bernasor and Datta, 1988).
In some regions nitrogen levels are increased by encouraging Azolla growth and P. distichum has emerged as a major weed under such regimes (Janiya and Moody, 1987; Krock et al., 1988).
In the Keoladeo National Park, India, P. distichum was apparently suppressed by the grazing of water buffalo. After removal of these animals, the weed expanded but was later brought under some degree of control by the grazing of wild pigs, geese and deer (Middleton, 1998).
Physical/mechanical control
Thorough preparation of the land during the 30 day period prior to transplanting, augmented with handweeding, provides effective control of P. distichum in the Philippines (Rahman, 1992). Increasing tillage frequency from one to three harrowings substantially reduces stands of the weed (Bernasor and Datta, 1988). In fields infested by seeds, overwintering rhizomes and stems, cultivation or diskings which normally eradicate small seedlings, only help to propagate the weed by cutting the stems and rhizomes into small pieces. Ploughing often promotes the dominance of plants with bulbs, stolons or rhizomes (Hsiao and Huang, 1989a). However, deep ploughing is an effective method of control (Noda and Obayashi, 1971), as the depth of emergence is less (3.25 cm on average) than that of other perennial plants of the Cyperaceae found in similar environments (Okuma et al., 1983). Moisture conditions are important for the success of mechanical disturbance: under wet conditions control may depend on deep burial, whereas under seasonally dry conditions, shallow tillage may suffice.
Samantha et al. (1995) emphasise the need for two hand weedings to control P. distichum in rice in Bangladesh.
Solarisation has been used with some success in Spain (Dalmau et al., 1993).
Chemical control
P. distichum tolerates most of the popular pre- and post-emergent herbicides. Resistance to post-emergent herbicides is attributed to anatomical features such as: thickening of the cell membranes of the epidermis, cortex and central portion; poor development of vascular bundles, and no air capacity in the central portion; and the accumulation of starch granules in the cortex and central regions (Noda and Obayasi, 1971). The accumulation of starch is partly responsible for the regenerative ability of isolated segments of the stem or rhizome. Glyphosate is the most widely used herbicide for the control of P. distichum (Okuma and Chikura, 1985; Manuel et al., 1979). Thiobencarb (Shad, 1986; Singh, 1992), molinate (Srinivasan and Subbian, 1991), haloxyfop or quizalofop (Rahman and Sanders, 1991), pretilachlor (Llorente and Evangelista, 1990), butachlor (Pradhan and Chettri, 1987; Bajwa et al., 1985), fluazifop (Okuma and Chikura, 1985), sethoxydim (Parker, 1982), paraquat (Manuel et al., 1979) and fluroxypyr plus triclopyr (Schultz, 2005) can also provide effective control, depending on the crop. Metolachlor, oxyfluorfen, prodiamine, and pendimethalin were most effective in leeks (Gilreath et al., 2008). Nicosulfuron is moderately effective in maize (James and Rahman, 1997).
Newer herbicides for rice include fenoxaprop (Reddy et al., 2000), bispyribac-sodium (Wang Qiang et al., 2000; He JinHao and Ma ZhaoJiang, 2000), pyanchor (pyribenzoxim) (Zhou XiaoJun et al., 2000), bensulfuron methyl and prosulfuron-ethyl (Sumiyoshi, 2000).
Glufosinate is also effective in conjunction with transgenic glufosinate-tolerant rice varieties (Yu LiuQing et al., 2005).
The use of pre-planting herbicides can reduce the need for extensive land preparation. The 30-day preparation period required to effectively control P. distichum can be reduced to 15 days when combined with glyphosate treatment. The combined use of low-tillage practices and herbicide treatment is increasing in popularity in areas where labour costs are high.
Biological Control
There are currently no biological control methods for P. distichum. The weed is an alternative host for many of the fungi, viruses, bacteria and nematodes that afflict crops in which the weed occurs.
References
Top of pageBebawi FF; Neugebohrn L, 1991. A Review of Plants of Northern Sudan, with Special Refererence to their Uses. Eschborn, Germany: GTZ, 294 pp.
Bor NL, 1960. The Grasses of Burma, Ceylon, India and Pakistan (Excluding Bambusae). Oxford, UK: Pergamon Press.
Brummitt RK, 1983. Report of the Committee for Spermatophyta: 25. Taxon, 32(2):279-284.
Campbell BD; Mitchell ND; Field TRO, 1999. Climate profiles of temperate C3 and subtropical C4 species in New Zealand pastures. New Zealand Journal of Agricultural Research, 42(3):223-233.
Chase A, 1929. The North American species of Paspalum. Contributions from the United States National Herbarium 28:46-52.
Clayton WD, 1989. 200. Gramineae (Paniceae, Isachneae and Aruninelleae). In: Flora Zambesiaca, Volume Ten, Part Three [ed. by Launert, E. \Pope, G. V.]. London, UK: Flora Zambesiaca Managing Committee, 231 pp.
Echarte AM; Clausen AM; Sala CA, 1992. Numeros chromosomicos y variabilidad morfologica de Paspalum distichum (Poaceae) en la provincia de Buenos Aires (Argentina). Darwiniana, 31:185-197.
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Falvey L; Hengmichai P, 1978. Third Report of the Thai-Australian Highland Agricultural Project. Chaiangmai, Thailand: Tippanetr Press, 54-56.
FAO, 2009. Grassland Index. Rome, Italy: FAO. http://www.fao.org/ag/AGP/AGPC/doc/GBASE/mainmenu.htm
Gould FW, 1965. The Grasses of Texas. Texas, USA: Texas A&M University Press.
Guedes M, 1981. Against Rejecting the Name Paspalum distichum L.: Comment on Proposal 528. Taxon, 30(1):301.
HSfliger E; Scholz H, 1980. Weeds of the subfamily Panicoideae, Paspalum paspalodes. In: Grass Weeds 1. Basel, Switzerland: Documenta CIBA-GEIGY, 103.
Labrada R, 1975. Some aspects of the incidence of weeds in Cuba. PANS, 21(3):308-312.
Layt T, 2001. Variety: 'Flexi-Green'. Application no. 97/101. Plant Varieties Journal, 14(2):48-49.
Li Y, 1981. Field Weeds and Weed Losses, Identification, Control, Quarantine. Jiansu, China: Jiangsu Science and Technology Publishing House (in Chinese).
Noltie HJ, 2000. Flora of Bhutan, Volume 3, Part 2. The Grasses of Bhutan. Edinburgh, UK: Royal Botanic Gardens, 457-883.
PlantNet, 2008. Flora of New South Wales. Flora of New South Wales. http://plantnet.rbgsyd.nsw.gov.au/floraonline.htm
Ranjit JD; Bhattarai AN, 1988. Crop Weeds and their Control in Nepal. Winrock Internatioanl, 30 pp.
Renvoize SA; Clayton WD, 1980. Proposal to Reject the Name Paspalum distichum L. Syst. Nat. ed. 10,2: 855 (1759). (Nom. rejic. prop.). Taxon, 29(2/3):339-340.
Robbins WW; Bellue MK; Ball WS, 1951. Weeds of California. Sacramento, USA: California State Printing Office.
Schulz T, 2005. [English title not available]. (A more reliable method of weed control.) Milchpraxis, 43(1):47-48.
Shad RA, 1986. Improving weed management in wetland rice. Progressive Farming, 6(1):49-53
Shukla U, 1996. The grasses of north-eastern India. Jodhpur, India: Scientific Publishers, 404 pp.
Smiley JF, 1922. Weeds of California and methods of Control. Sacramento, California: California State Printing Office.
Townsend CC; Guest E; Al-Rawi A, 1968. Flora of Iraq 9. Republic of Iraq: Ministry of Agriculture, 89.
Tsvelev NN, 1984. Grasses of the Soviet Union Part II. ed. Fedorov AA. Balkema/Rotterdam Russian Translation Series 8.
Verloove F; Reynders M, 2007. Studies in the genus Paspalum (Paniceae, Poacea) in Europe - 1. Paspalum distichum subsp. paucispicatum, an overlooked taxon in France. Willdenowia, 37(1):199-204.
Wang ZR, 1990. Farmland Weeds in China. Beijing, China: Agricultural Publishing House.
Wilkinson RE; Jacques, 1979. How to Know the Weeds. Dubuque, Iowa: WC Brown Company.
Zhou XiaoJun; He JinHao; Ma ZhaoJiang, 2000. Pyanchor in controlling weeds in direct seeded rice. Acta Agriculturae Zhejiangensis, 12(6):349-351.
Distribution References
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Clayton WD, 1989. Gramineae (Paniceae, Isachneae and Aruninelleae). In: Flora Zambesiaca, Ten (Three) [ed. by Launert E, Pope GV]. London, UK: Flora Zambesiaca Managing Committee. 231 pp.
Echarte AM, Clausen AM, Sala CA, 1992. (Numeros chromosomicos y variabilidad morfologica de Paspalum distichum (Poaceae) en la provincia de Buenos Aires (Argentina)). In: Darwiniana, 31 185-197.
Falvey L, Hengmichai P, 1978. Third Report of the Thai-Australian Highland Agricultural Project., Chaiangmai, Thailand: Tippanetr Press. 54-56.
Labrada R, 1975. Some aspects of the incidence of weeds in Cuba. PANS. 21 (3), 308-312.
Li Y, 1981. Field Weeds and Weed Losses, Identification, Control, Quarantine., Jiansu, China: Jiangsu Science and Technology Publishing House (in Chinese).
Noltie HJ, 2000. Flora of Bhutan. In: The Grasses of Bhutan, 3 (2) Edinburgh, UK: Royal Botanic Gardens. 437 pp.
Ranjit JD, Bhattarai AN, 1988. Crop Weeds and their Control in Nepal., Winrock International. 30 pp.
Shukla U, 1996. The grasses of north-eastern India. Jodphur, India: Scientific Publishers. 404 pp.
Stace C, 1991. New Flora of the British Isles. Cambridge, UK: Cambridge University Press.
Townsend CC, Guest E, Al-Rawi A, 1968. Flora of Iraq 9. In: Republic of Iraq: Ministry of Agriculture, 89.
Tsvelev NN, 1984. Grasses of the Soviet Union Part II. In: Balkema/Rotterdam Russian Translation Series 8, [ed. by Fedorov AA].
Wang Z R, 1990. Farmland Weeds in China. Beijing, China: Agricultural Publishing House.
Links to Websites
Top of pageWebsite | URL | Comment |
---|---|---|
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway | https://doi.org/10.5061/dryad.m93f6 | Data source for updated system data added to species habitat list. |
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