Diodia teres (poorjoe)
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PicturesTop of page
|Caption||D. teres: plant in leaf and flower.|
|Copyright||Kurt G. Kissmann|
|Flowering plant||D. teres: plant in leaf and flower.||Kurt G. Kissmann|
|Caption||Seedling of D. teres.|
|Copyright||Kurt G. Kissmann|
|Seedling||Seedling of D. teres.||Kurt G. Kissmann|
|Title||Fruit and seed|
|Caption||D. teres: fruits and seed; Coccus (a & b) dorsal and ventral sides; Seed (c & d) dorsal and ventral sides.|
|Copyright||Kurt G. Kissmann|
|Fruit and seed||D. teres: fruits and seed; Coccus (a & b) dorsal and ventral sides; Seed (c & d) dorsal and ventral sides.||Kurt G. Kissmann|
IdentityTop of page
Preferred Scientific Name
- Diodia teres Walt. (1788)
Preferred Common Name
Other Scientific Names
International Common Names
- English: rough buttonweed
- Portuguese: mata-pasto
Local Common Names
- Brazil: mata pasto; quebra tijela de folha estreita
Summary of InvasivenessTop of page
D. teres is an annual plant with high reproductive potential. It is reported to be an invasive species in some US states and in Brazil. It is most conspicuous in natural pastures, however its impact is generally low compared with other weedy species.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Gentianales
- Family: Rubiaceae
- Genus: Diodia
- Species: Diodia teres
Notes on Taxonomy and NomenclatureTop of page
Maguire et al. (1972) concluded that D. prostrata Sw. and D. teres Walt. should not be treated as separate species but as interrelated subspecies. They identified the following subspecies, varieties and forms of D. teres: D. teres subsp. teres (and varieties), D. teres subsp. angustata var. angustata f. angustata, D. teres subsp. angustata var. angustata f. latior, D. teres subsp. prostrata var. prostrata f. leiocarpa, D. teres subsp. prostrata var. prostrata f. prostrata and D. teres subsp. prostrata var. prostrata f. latifolia. The differences between subspecies teres, angustata and prostrata are based on floral characters and stem hairs. Five varieties are listed by USDA-NRCS (2003): vars teres, angustata, hirsutior, hystricina and oblongifolia. For the purpose of this data sheet, no distinctions are drawn between subspecies and varieties.
DescriptionTop of page
D. teres is an annual, herbaceous forb, presenting variable morphological characteristics. It can be prostrate or erect, 10-40 (-80) cm high. Taproot slender and branching, secondary roots shallow. Stem generally branched with nearly circular spread; circular or slightly angular in cross section, densely hairy, reddish brown. Leaves in pairs, opposite, their bases clasping the stem at its joints, appendage of fused stipules, presenting long bristles. Blades green, linear to narrowly elliptic, tapering to a long point, smooth margins, surfaces roughened by stiff hairs. Flowers in groups of two or three (-six), located at the base of leaves or leaf axils, calyx with four lanceolate sepals 1 mm long, corolla of fused petals forming a tube 4-5 mm long, with four equal lobes, whitish-pink to lavender. Fruits are ovoid schizocarps with two persistent sepals at the apex, at maturity splitting from the apex in two cocci, every coccus with one seed, seeds oboval in outline 2.5-4 mm long, light brown.
Seedling with light-green hypocotyl. Cotyledon blades with short petiole, slightly thickened. Leaves opposite, with short petiole, not much different from the blade. Basal appendage of bristly branched stipule, developing earlier than the juvenile leaf blades. Hypocotyl, epicotyl and stem bearing short stiff and some longer downwardly directed hairs.
Plant TypeTop of page
DistributionTop of page
D. teres is native to the Americas and is present in parts of the USA, Mexico, Central America, Caribbean and South America.
Distribution TableTop of page
The 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.
|Country||Distribution||Last Reported||Origin||First Reported||Invasive||References||Notes|
|-Indian Punjab||Present||Mehra et al., 1987|
|Madagascar||Present||Missouri Botanical Garden, 2003|
|-New Jersey||Present||Native||USDA-NRCS, 2003|
|-New Mexico||Present||Native||USDA-NRCS, 2003|
|-New York||Present||Native||USDA-NRCS, 2003|
|-North Carolina||Present||Native||USDA-NRCS, 2003|
|-Rhode Island||Present||Native||USDA-NRCS, 2003|
|-South Carolina||Present||Native||USDA-NRCS, 2003|
|-West Virginia||Present||Native||USDA-NRCS, 2003|
CENTRAL AMERICA AND CARIBBEAN
|Belize||Present||Native||Missouri Botanical Garden, 2003|
|Costa Rica||Present||Native||Missouri Botanical Garden, 2003|
|Dominican Republic||Present||Native||NYBG, 2004|
|Honduras||Present||Native||Missouri Botanical Garden, 2003|
|Jamaica||Present||Native||Wunderlin & Hansen, 2003|
|Netherlands Antilles||Present||Maguire et al., 1972|
|Nicaragua||Present||Native||Missouri Botanical Garden, 2003|
|Panama||Present||Native||Missouri Botanical Garden, 2003|
|Bolivia||Present||Native||Missouri Botanical Garden, 2003|
|-Mato Grosso do Sul||Widespread||Native||Invasive||Lorenzi, 1982|
|-Minas Gerais||Widespread||Native||Invasive||Lorenzi, 1982|
|-Pernambuco||Restricted distribution||Introduced||Invasive||Kissmann & Groth, 2000|
|-Sao Paulo||Widespread||Native||Invasive||Lorenzi, 1982|
|Colombia||Present||Native||Wunderlin & Hansen, 2003|
|Ecuador||Present||Native||Missouri Botanical Garden, 2003|
|Venezuela||Present||Native||Wunderlin & Hansen, 2003|
HabitatTop of page
D. teres tolerates poor, sandy and shallow soils, under which conditions it can outcompete other vegetation. In native pastures, cattle do not favour this plant for grazing which allows it to spread. When fertilizer is applied, however, grasses are benefited more than D. teres.
Habitat ListTop of page
|Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Disturbed areas||Present, no further details|
|Managed forests, plantations and orchards||Present, no further details|
|Natural grasslands||Present, no further details|
Hosts/Species AffectedTop of page
D. teres is an agricultural weed contributing to weed problems in a number of crops and also pastures.
Biology and EcologyTop of page
Physiology and Phenology
Growth analyses have shown that genetic changes in an agricultural weed population of D. teres resulted in earlier establishment and faster early growth compared with a coastal non-weed population in North Carolina, USA (Jordan, 1989a, b).
Plants reproduce by seeds that are dispersed within cocci. Seeds germinate in the spring or summer. The life cycle lasts 90-110 days.
D. teres is not frost tolerant. Best conditions for growth are during the hot months of the year, provided there is sufficient soil moisture.
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Absolute minimum temperature (ºC)||0||0|
|Mean annual temperature (ºC)||0||0|
|Mean maximum temperature of hottest month (ºC)||0||0|
|Mean minimum temperature of coldest month (ºC)||0||0|
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Dry season duration||0||0||number of consecutive months with <40 mm rainfall|
|Mean annual rainfall||0||0||mm; lower/upper limits|
Soil TolerancesTop of page
Special soil tolerances
Means of Movement and DispersalTop of page
Natural Dispersal (non-biotic)
Seeds drop to the ground close to or beneath the parent plant.
Vector Transmission (biotic)
Seed dispersal is not assisted by vectors.
Seeds may be introduced as contaminants of crops with small seeds or spread by farm vehicles and machinery.
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|True seeds (inc. grain)||seeds||No||Yes||Pest or symptoms usually visible to the naked eye|
|Plant parts not known to carry the pest in trade/transport|
|Bulbs, Tubers, Corms, Rhizomes|
|Flowers, Inflorescences, Cones, Calyx|
|Fruits (inc. pods)|
|Growing medium accompanying plants|
|Seedlings, Micropropagated plants|
|Stems (above ground), Shoots, Trunks, Branches|
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page
D. teres may contribute towards economic losses due to weeds in agricultural crops.
Environmental ImpactTop of page
If unchecked, D. teres can form dense infestations. However, because this is an annual plant, these are only present for limited periods.
Risk and Impact FactorsTop of page
- Competition - monopolizing resources
- Negatively impacts agriculture
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Highly adaptable to different environments
- Invasive in its native range
- Proved invasive outside its native range
Likelihood of entry/control
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
- Difficult/costly to control
Similarities to Other Species/ConditionsTop of page
Several species in the Rubiaceae family resemble D. teres. The genus Diodia is characterized by having bilocular ovaries, fruits being schizocarps splitting from the apex in two indehiscent cocci. D. teres is an annual plant and is distinguished by the following: ventral side of mature cocci with two excavated areas; dorsal side with one main median obtusely angled ridge; calyx lobes nearly equal; corolla 4-5 mm long, opening in four lobes, colour whitish-pink to lavender.
Prevention and ControlTop of pageCultural Control
Good crop management reduces D. teres and other weed problems.Mechanical Control
Tillage of the soil helps to control D. teres.Chemical Control
Sulfometuron (Miller, 1990) and napropamide + netribuzin (Reynolds and Crowley, 1981) have been reported to be effective against D. teres in the USA. However, it is more usual that herbicides are selected for the control of more important weeds that are also present with D. teres.
ReferencesTop of page
Jordan N, 1989. Path analysis of growth differences between weed and nonweed populations of poorjoe (Diodia teres) in competition with soybean (Glycine max). Weed Science, 37(1):129-136
Jordan N, 1989. Predicted evolutionary response to selection for tolerance of soybean (Glycine max) and intraspecific competition on nonweed population of poorjoe (Diodia teres). Weed Science, 37(3):451-457
Kissmann KG, Groth D, 2000. Plantas Infestantes e Nocivas, Tomo III, edition 2. Brazil: BASF, 400-403.
Lorenzi H, 1982. Plantas Daninhas do Brasil. Author's edition. Nova Odessa, San Paulo, Brazil: H. Lorenzi, 400 pp.
Maguire B, et al., 1972. The botany of the Guayana Highland - part IX. Memoirs of the New York Botanical Garden, 23: 798-801.
Mehra SP, Sidhu PS, Gill HS, 1987. Studies on weed control in irrigated groundnut. Journal of Research, Punjab Agricultural University, 24(1):8-14
Miller JH, 1990. Herbaceous weed control trials with a planting machine and a crawler-tractor sprayer - fourth year pine response. Proceedings of the 43rd Annual Meeting of the Southern Weed Science Society, 233-244
Missouri Botanical Garden, 2003. VAScular Tropicos database. St. Louis, USA: Missouri Botanical Garden. http://mobot.mobot.org/W3T/Search/vast.html.
NYBG, 2004. The Virtual Herbarium of the New York Botanical Garden, USA. http://scisun.nybg.org:8890/searchdb/owa/wwwspecimen.searchform.
Reynolds DB, Crowley RH, 1981. Crabgrass and poorjoe control in commercial tomato production. Proceedings 34th Annual Meeting Southern Weed Science Society., 122
USDA-NRCS, 2003. The PLANTS Database, Version 3.5. National Plant Data Center, Baton Rouge, USA. http://plants.usda.gov.
Wunderlin RP, Hansen BF, 2003. Atlas of Florida Vascular Plants. Institute for Systematic Biology, University of South Florida, Tampa, USA. http://www.plantatlas.usf.edu/.
Top of page
- = Present, no further details
- = Evidence of pathogen
- = Widespread
- = Last reported
- = Localised
- = Presence unconfirmed
- = Confined and subject to quarantine
- = See regional map for distribution within the country
- = Occasional or few reports