Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Diodia teres



Diodia teres (poorjoe)


  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Diodia teres
  • Preferred Common Name
  • poorjoe
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • 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.

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D. teres: plant in leaf and flower.
TitleFlowering plant
CaptionD. teres: plant in leaf and flower.
Copyright©Kurt G. Kissmann
D. teres: plant in leaf and flower.
Flowering plantD. teres: plant in leaf and flower.©Kurt G. Kissmann
Seedling of D. teres.
CaptionSeedling of D. teres.
Copyright©Kurt G. Kissmann
Seedling of D. teres.
SeedlingSeedling of D. teres.©Kurt G. Kissmann
D. teres: fruits and seed; Coccus (a & b) dorsal and ventral sides; Seed (c & d) dorsal and ventral sides.
TitleFruit and seed
CaptionD. teres: fruits and seed; Coccus (a & b) dorsal and ventral sides; Seed (c & d) dorsal and ventral sides.
Copyright©Kurt G. Kissmann
D. teres: fruits and seed; Coccus (a & b) dorsal and ventral sides; Seed (c & d) dorsal and ventral sides.
Fruit and seedD. teres: fruits and seed; Coccus (a & b) dorsal and ventral sides; Seed (c & d) dorsal and ventral sides.©Kurt G. Kissmann


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Preferred Scientific Name

  • Diodia teres Walt. (1788)

Preferred Common Name

  • poorjoe

Other Scientific Names

  • Diodia prostrata Sw.

International Common Names

  • English: rough buttonweed
  • Portuguese: mata-pasto

Local Common Names

  • Brazil: mata pasto; quebra tijela de folha estreita

EPPO code

  • DIQTE (Diodia teres)

Summary of Invasiveness

Top 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 Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Gentianales
  •                         Family: Rubiaceae
  •                             Genus: Diodia
  •                                 Species: Diodia teres

Notes on Taxonomy and Nomenclature

Top 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.


Top 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.


Top 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 Table

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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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes


IndiaPresentPresent based on regional distribution.
-Indian PunjabPresentMehra et al., 1987


MadagascarPresentMissouri Botanical Garden, 2003

North America

MexicoPresentNativeNYBG, 2004
USAPresentPresent based on regional distribution.
-AlabamaPresentNativeUSDA-NRCS, 2003
-ArizonaPresentNativeUSDA-NRCS, 2003
-ArkansasPresentNativeUSDA-NRCS, 2003
-CaliforniaPresentNativeUSDA-NRCS, 2003
-ConnecticutPresentNativeUSDA-NRCS, 2003
-DelawarePresentNativeUSDA-NRCS, 2003
-FloridaPresentNativeUSDA-NRCS, 2003
-GeorgiaPresentNativeUSDA-NRCS, 2003
-IllinoisPresentNativeUSDA-NRCS, 2003
-IndianaPresentNativeUSDA-NRCS, 2003
-IowaPresentNativeUSDA-NRCS, 2003
-KansasPresentNativeUSDA-NRCS, 2003
-KentuckyPresentNativeUSDA-NRCS, 2003
-LouisianaPresentNativeUSDA-NRCS, 2003
-MarylandPresentNativeUSDA-NRCS, 2003
-MassachusettsPresentNativeUSDA-NRCS, 2003
-MichiganPresentNativeUSDA-NRCS, 2003
-MississippiPresentNativeUSDA-NRCS, 2003
-MissouriPresentNativeUSDA-NRCS, 2003
-New JerseyPresentNativeUSDA-NRCS, 2003
-New MexicoPresentNativeUSDA-NRCS, 2003
-New YorkPresentNativeUSDA-NRCS, 2003
-North CarolinaPresentNativeUSDA-NRCS, 2003
-OhioPresentNativeUSDA-NRCS, 2003
-OklahomaPresentNativeUSDA-NRCS, 2003
-PennsylvaniaPresentNativeUSDA-NRCS, 2003
-Rhode IslandPresentNativeUSDA-NRCS, 2003
-South CarolinaPresentNativeUSDA-NRCS, 2003
-TennesseePresentNativeUSDA-NRCS, 2003
-TexasPresentNativeUSDA-NRCS, 2003
-VirginiaPresentNativeUSDA-NRCS, 2003
-West VirginiaPresentNativeUSDA-NRCS, 2003
-WisconsinPresentNativeUSDA-NRCS, 2003

Central America and Caribbean

BelizePresentNativeMissouri Botanical Garden, 2003
Costa RicaPresentNativeMissouri Botanical Garden, 2003
CubaPresentNativeNYBG, 2004
Dominican RepublicPresentNativeNYBG, 2004
HondurasPresentNativeMissouri Botanical Garden, 2003
JamaicaPresentNativeWunderlin and Hansen, 2003
Netherlands AntillesPresentMaguire et al., 1972
NicaraguaPresentNativeMissouri Botanical Garden, 2003
PanamaPresentNativeMissouri Botanical Garden, 2003

South America

BoliviaPresentNativeMissouri Botanical Garden, 2003
BrazilPresentPresent based on regional distribution.
-GoiasWidespreadNative Invasive Lorenzi, 1982
-Mato Grosso do SulWidespreadNative Invasive Lorenzi, 1982
-Minas GeraisWidespreadNative Invasive Lorenzi, 1982
-ParanaWidespreadNative Invasive Lorenzi, 1982
-PernambucoRestricted distributionIntroduced Invasive Kissmann and Groth, 2000
-Sao PauloWidespreadNative Invasive Lorenzi, 1982
ColombiaPresentNativeWunderlin and Hansen, 2003
EcuadorPresentNativeMissouri Botanical Garden, 2003
GuyanaPresentNativeNYBG, 2004
PeruPresentNativeNYBG, 2004
VenezuelaPresentNativeWunderlin and Hansen, 2003


Top 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 List

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Terrestrial – ManagedCultivated / agricultural land Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details
Disturbed areas Present, no further details
Terrestrial ‑ Natural / Semi-naturalNatural grasslands Present, no further details

Hosts/Species Affected

Top of page D. teres is an agricultural weed contributing to weed problems in a number of crops and also pastures.

Growth Stages

Top of page Vegetative growing stage

Biology and Ecology

Top 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).

Reproductive Biology

Plants reproduce by seeds that are dispersed within cocci. Seeds germinate in the spring or summer. The life cycle lasts 90-110 days.

Environmental Requirements

D. teres is not frost tolerant. Best conditions for growth are during the hot months of the year, provided there is sufficient soil moisture.

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
0 0 0 0

Air Temperature

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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


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ParameterLower limitUpper limitDescription
Dry season duration00number of consecutive months with <40 mm rainfall
Mean annual rainfall00mm; lower/upper limits

Means of Movement and Dispersal

Top 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.

Accidental Introduction

Seeds may be introduced as contaminants of crops with small seeds or spread by farm vehicles and machinery.

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
True seeds (inc. grain) seeds Yes Pest or symptoms usually visible to the naked eye
Plant parts not known to carry the pest in trade/transport
Fruits (inc. pods)
Growing medium accompanying plants
Seedlings/Micropropagated plants
Stems (above ground)/Shoots/Trunks/Branches

Impact Summary

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Animal/plant collections None
Animal/plant products None
Biodiversity (generally) None
Crop production Negative
Environment (generally) None
Fisheries / aquaculture None
Forestry production None
Human health None
Livestock production Negative
Native fauna None
Native flora Negative
Rare/protected species None
Tourism None
Trade/international relations None
Transport/travel None


Top of page D. teres may contribute towards economic losses due to weeds in agricultural crops.

Environmental Impact

Top 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 Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Highly adaptable to different environments
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Negatively impacts agriculture
Impact mechanisms
  • Competition - monopolizing resources
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/Conditions

Top 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 Control

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Due 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.

Cultural 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.


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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.

NYBG, 2004. The Virtual Herbarium of the New York Botanical Garden, USA.

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.

Wunderlin RP; Hansen BF, 2003. Atlas of Florida Vascular Plants. Institute for Systematic Biology, University of South Florida, Tampa, USA.

Distribution Maps

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