Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Cynoglossum officinale
(hound's tongue)

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Datasheet

Cynoglossum officinale (hound's tongue)

Summary

  • Last modified
  • 14 July 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Cynoglossum officinale
  • Preferred Common Name
  • hound's tongue
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • C. officinale, native to Eurasia, is a highly invasive weed now present throughout much of North America, probably introduced as a seed contaminant. It is a common weed of rangeland and spreads locally attached to the fur of livestock. Its presence r...

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Pictures

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PictureTitleCaptionCopyright
Cynoglossum officinale (hound's tongue); flowering plant. Dunavecse, Hungary.
TitleHabit
CaptionCynoglossum officinale (hound's tongue); flowering plant. Dunavecse, Hungary.
Copyright©Robert Vidéki/Doronicum Kft./Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); flowering plant. Dunavecse, Hungary.
HabitCynoglossum officinale (hound's tongue); flowering plant. Dunavecse, Hungary.©Robert Vidéki/Doronicum Kft./Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); flowering plant. USA.
TitleFlowering plant
CaptionCynoglossum officinale (hound's tongue); flowering plant. USA.
Copyright©Mary Ellen (Mel) Harte/Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); flowering plant. USA.
Flowering plantCynoglossum officinale (hound's tongue); flowering plant. USA.©Mary Ellen (Mel) Harte/Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); flowering plant. Virngrund, Germany. May, 2006
TitleFlowering plant
CaptionCynoglossum officinale (hound's tongue); flowering plant. Virngrund, Germany. May, 2006
Copyright©Bernd Haynold - CC BY-SA 3.0
Cynoglossum officinale (hound's tongue); flowering plant. Virngrund, Germany. May, 2006
Flowering plantCynoglossum officinale (hound's tongue); flowering plant. Virngrund, Germany. May, 2006©Bernd Haynold - CC BY-SA 3.0
Cynoglossum officinale (hound's tongue); close-up of flowers. Unterfranken, Germany. June, 2008.
TitleFlowers
CaptionCynoglossum officinale (hound's tongue); close-up of flowers. Unterfranken, Germany. June, 2008.
Copyright©Fornax/Wikipedia - CC BY-SA 3.0
Cynoglossum officinale (hound's tongue); close-up of flowers. Unterfranken, Germany. June, 2008.
FlowersCynoglossum officinale (hound's tongue); close-up of flowers. Unterfranken, Germany. June, 2008.©Fornax/Wikipedia - CC BY-SA 3.0
Cynoglossum officinale (hound's tongue); fruits. USA.
TitleFruits
CaptionCynoglossum officinale (hound's tongue); fruits. USA.
Copyright©Mary Ellen (Mel) Harte/Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); fruits. USA.
FruitsCynoglossum officinale (hound's tongue); fruits. USA.©Mary Ellen (Mel) Harte/Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); seeds. (note scale). USA.
TitleSeeds
CaptionCynoglossum officinale (hound's tongue); seeds. (note scale). USA.
Copyright©Steve Hurst/USDA NRCS PLANTS Database/Bugwood.org - CC BY-NC 3.0 US
Cynoglossum officinale (hound's tongue); seeds. (note scale). USA.
SeedsCynoglossum officinale (hound's tongue); seeds. (note scale). USA.©Steve Hurst/USDA NRCS PLANTS Database/Bugwood.org - CC BY-NC 3.0 US

Identity

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Preferred Scientific Name

  • Cynoglossum officinale L.

Preferred Common Name

  • hound's tongue

International Common Names

  • English: begger's lice; common bur; common houndstongue; dog burr; dog's tongue; glovewort; houndstongue; woolmat
  • Spanish: lengua de perro comun
  • French: cynoglosse officinale; herbe d'antal; langue de chien; langue-de-chien

Local Common Names

  • Germany: Echte Hundszunge; Gemeine Hundszunge
  • Italy: cinoglossa
  • Netherlands: hondstong
  • Sweden: hundtunga

EPPO code

  • CYWOF (Cynoglossum officinale)

Summary of Invasiveness

Top of page C. officinale, native to Eurasia, is a highly invasive weed now present throughout much of North America, probably introduced as a seed contaminant. It is a common weed of rangeland and spreads locally attached to the fur of livestock. Its presence reduces the availability of forage grasses and it is poisonous to livestock if ingested. It is possible that further introductions may occur to other countries with similar climates.

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Boraginales
  •                         Family: Boraginaceae
  •                             Genus: Cynoglossum
  •                                 Species: Cynoglossum officinale

Notes on Taxonomy and Nomenclature

Top of page Cynoglossum officinale is the accepted scientific name of this weed and no subspecies have been reported. The genus Cynoglossum belongs to family Boraginaceae (Borage family). The common name in English is 'hound's tongue', derived from the shape of the leaves, though it also known by a variety of other names (Macoun, 1884; Clark and Fletcher, 1909; Cockayne, 1961; Greatorex, 1966; Scoggan, 1978; Muenscher, 1980).

Description

Top of page C. officinale is a herbaceous weed, producing either single or multiple erect hairy stems, 0.3 to 1.2 m tall and a thick, woody taproot. It has rough, hairy, alternate leaves, 10-30 cm long and 2-5 cm wide, lanceolate to oblong, i.e. shaped like hound's tongue (Upadhyaya et al., 1988). Lower leaves with short petioles and in rosettes. Upper leaves clasp the stem. Leaf margins are entire. The flowers are dull reddish-purple in colour, with five petals, and are present in axils of upper leaves. The inflorescence is a raceme. Indehiscent burred fruits, which are brown to greyish-brown in colour, consist of four nutlets. The seed coat is dark brown to black with a white embryo inside.

Plant Type

Top of page Biennial
Broadleaved
Herbaceous
Perennial
Seed propagated

Distribution

Top of page C. officinale has a broad native range in the temperate zones from western Europe (Tutin et al., 1972) to central Asia (USDA-ARS, 2003), and has been introduced to the USA (Cochrane, 1975; Dickerson and Fay, 1982; Knight et al., 1984), and Canada (Breitung, 1957a, b; Boivin, 1966; Scoggan, 1978).

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

Asia

ArmeniaPresentNativeUSDA-ARS, 2003
AzerbaijanPresentNativeUSDA-ARS, 2003
Georgia (Republic of)PresentNativeUSDA-ARS, 2003
IranPresentNativeUSDA-ARS, 2003
KazakhstanPresentNativeUSDA-ARS, 2003
KyrgyzstanPresentNativeUSDA-ARS, 2003
TurkeyPresentNativeUSDA-ARS, 2003

North America

CanadaPresentPresent based on regional distribution.
-AlbertaPresentIntroduced Invasive Upadhyaya et al., 1988; Upadhyaya and Cranston, 1991
-British ColumbiaPresentIntroduced1922 Invasive Anon., 2002a; Taylor and MacBryde, 1977
-ManitobaPresent, few occurrencesIntroducedUpadhyaya et al., 1988; Upadhyaya and Cranston, 1991
-Newfoundland and LabradorAbsent, intercepted onlyIntroduced Not invasive Upadhyaya et al., 1988; Upadhyaya and Cranston, 1991
-OntarioPresentIntroducedbefore 1859 Invasive Macoun, 1884; Upadhyaya et al., 1988
-Prince Edward IslandAbsent, intercepted onlyIntroduced Not invasive Upadhyaya et al., 1988; Upadhyaya and Cranston, 1991
-QuebecPresentIntroduced Invasive Macoun, 1884
-SaskatchewanPresent, few occurrencesIntroducedUpadhyaya et al., 1988
USAPresentPresent based on regional distribution.
-AlabamaPresentIntroducedUSDA-NRCS, 2002
-ArizonaPresentIntroducedUSDA-NRCS, 2002
-ArkansasPresentIntroducedUSDA-NRCS, 2002
-CaliforniaPresentIntroducedUSDA-NRCS, 2002
-ColoradoPresentIntroduced Invasive USDA-NRCS, 2002
-ConnecticutPresentIntroducedUSDA-NRCS, 2002
-DelawarePresentIntroducedUSDA-NRCS, 2002
-GeorgiaPresentIntroducedUSDA-NRCS, 2002
-IdahoPresentIntroducedUSDA-NRCS, 2002
-IllinoisPresentIntroducedUSDA-NRCS, 2002
-IndianaPresentIntroducedUSDA-NRCS, 2002
-IowaPresentIntroducedUSDA-NRCS, 2002
-KansasPresentIntroducedUSDA-NRCS, 2002
-KentuckyPresentIntroducedUSDA-NRCS, 2002
-MainePresentIntroducedUSDA-NRCS, 2002
-MarylandPresentIntroducedUSDA-NRCS, 2002
-MassachusettsPresentIntroducedUSDA-NRCS, 2002
-MichiganPresentIntroducedUSDA-NRCS, 2002
-MinnesotaPresentIntroducedUSDA-NRCS, 2002
-MississippiPresentIntroducedUSDA-NRCS, 2002
-MissouriPresentIntroducedUSDA-NRCS, 2002
-MontanaPresentIntroduced Invasive USDA-NRCS, 2002
-NebraskaPresentIntroducedUSDA-NRCS, 2002
-NevadaPresentIntroduced Invasive USDA-NRCS, 2002
-New HampshirePresentIntroducedUSDA-NRCS, 2002
-New JerseyPresentIntroducedUSDA-NRCS, 2002
-New MexicoPresentIntroducedUSDA-NRCS, 2002
-New YorkPresentIntroducedUSDA-NRCS, 2002
-North CarolinaPresentIntroducedUSDA-NRCS, 2002
-North DakotaPresentIntroducedUSDA-NRCS, 2002
-OhioPresentIntroducedUSDA-NRCS, 2002
-OregonPresentIntroduced Invasive USDA-NRCS, 2002
-PennsylvaniaPresentIntroducedUSDA-NRCS, 2002
-Rhode IslandPresentIntroducedUSDA-NRCS, 2002
-South DakotaPresentIntroduced Invasive USDA-NRCS, 2002
-TennesseePresentIntroducedUSDA-NRCS, 2002
-UtahPresentIntroducedUSDA-NRCS, 2002
-VermontPresentIntroducedUSDA-NRCS, 2002
-VirginiaPresentIntroducedUSDA-NRCS, 2002
-WashingtonPresentIntroduced Invasive USDA-NRCS, 2002
-West VirginiaPresentIntroducedUSDA-NRCS, 2002
-WisconsinPresentIntroducedUSDA-NRCS, 2002
-WyomingPresentIntroduced Invasive USDA-NRCS, 2002

Europe

AlbaniaPresentNativeUSDA-ARS, 2003
AustriaPresentNativeUSDA-ARS, 2003
BelarusPresentNativeUSDA-ARS, 2003
BelgiumPresentNativeBritton, 1951
BulgariaPresentNativeUSDA-ARS, 2003
Czech RepublicPresentNativeUSDA-ARS, 2003
DenmarkPresentNativeBritton, 1951
EstoniaPresentNativeUSDA-ARS, 2003
FinlandPresentNativeUSDA-ARS, 2003
FrancePresentNativeUSDA-ARS, 2003
GermanyPresentNativeUSDA-ARS, 2003
GreecePresentNativeUSDA-ARS, 2003
HungaryPresentNativeUSDA-ARS, 2003
IcelandPresentLove and Love, 1956
IrelandPresentNativeUSDA-ARS, 2003
ItalyPresentNativeUSDA-ARS, 2003
LatviaPresentNativeUSDA-ARS, 2003
LithuaniaPresentNativeUSDA-ARS, 2003
NetherlandsPresentNativeFreijsen et al., 1980
NorwayPresentNativeUSDA-ARS, 2003
PolandPresentNativeSkalinska et al., 1959
RomaniaPresentNativeUSDA-ARS, 2003
Russian FederationPresentPresent based on regional distribution.
-Central RussiaPresentNativeUSDA-ARS, 2003
-Eastern SiberiaPresentNativeUSDA-ARS, 2003
-Northern RussiaPresentNativeUSDA-ARS, 2003
-Southern RussiaPresentNativeUSDA-ARS, 2003
-Western SiberiaPresentNativeUSDA-ARS, 2003
SlovakiaPresentNativeUSDA-ARS, 2003
SpainPresentNativeUSDA-ARS, 2003
SwedenPresentNativeUSDA-ARS, 2003
SwitzerlandPresentNativeUSDA-ARS, 2003
UKPresentNativeCockayne, 1961
UkrainePresentNativeUSDA-ARS, 2003
Yugoslavia (Serbia and Montenegro)PresentNativeUSDA-ARS, 2003

History of Introduction and Spread

Top of page C. officinale is considered native to Eurasia (Scoggan, 1978). It was probably introduced to North America as a contaminantion of cereal seeds (Knight et al., 1984). It was reported as common around Montreal, Quebec, and present in Ontario, Canada, as early as the 1880s (Macoun, 1884), with herbarium specimens collected in Ontario in 1859 and in western Canada in 1922 (Upadhyaya et al., 1988) indicating its spread. It was already reported as a troublesome weed in Canada before 1910 (Clarke and Fletcher, 1909).

Risk of Introduction

Top of page There is a high risk of further introduction of C. officinale to other countries with similar temperate climates as a contaminant of seed, wool or other livestock products. It is on the noxious weed lists for seven states of the USA (USDA-NRCS, 2002).

Habitat

Top of page C. officinale is a weed of temperate regions. It is found in rangelands, pastures, roadsides and waste places, and abandoned croplands (Alex and Switzer, 1976; Scoggan, 1978; Dickerson and Fay, 1982). It has been reported to occur in eastern North America on gravelly, somewhat limey soils (Meunscher, 1980), in the UK in sandy areas (Cockayne, 1961) and in old dune-grassland with dry sandy soils (Boorman, 1982), in the Netherlands on calcareous costal dunes, with high soil nitrogen (Freijsen et al., 1980) and in eastern Canada on rocky pastures in limestone regions (Frankton and Mulligan, 1970). Clapham et al. (1962) reported its occurrence in grassy places and borders of woods on dry soils, on gravel, sand, limestone, or chalk, near the sea. In British Columbia, Canada, it occurs on disturbed sites of the interior Douglas fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa)-bunchgrass biogeoclimatic zones (Taylor and McBryde, 1977). These zones have cold winters and hot dry summers. It is also found in many clear-cut logged areas (Cranston and Pethybridge, 1986) and grows in grasslands and low- to mid-elevation forests in British Columbia, Canada (Anon., 2002b).

Habitat List

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CategoryHabitatPresenceStatus
Littoral
Coastal areas Present, no further details
Terrestrial-managed
Disturbed areas Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Managed grasslands (grazing systems) Present, no further details Harmful (pest or invasive)
Rail / roadsides Present, no further details Harmful (pest or invasive)
Terrestrial-natural/semi-natural
Natural grasslands Present, no further details Harmful (pest or invasive)

Hosts/Species Affected

Top of page C. officinale is mainly a weed of grasslands, also forests, but can also be a problem in cultivated crops,

Biology and Ecology

Top of page Genetics

The diploid chromosome number of 2n=24 has been reported in C. officinale plants obtained from Ontario, Canada (Mulligan, 1957), Belgium, Denmark, the USA (Britton, 1951), Iceland (Love and Love, 1956), and Poland (Skalinska et al., 1959).

Physiology and Phenology

C. officinale is generally considered a biennial or short-lived perennial. Seedlings emerge in both spring and autumn and the rosettes bolt in the second year. Its deep root system gives it a competitive advantage over grasses under conditions of moisture stress. The C. officinale leaf surface is covered with uniseriate trichomes (hairs), which become more abundant as light intensity declines (Upadhyaya and Furness, 1994) and ultraviolet-B radiation levels above ambient have been reported to reduce C. officinale leaf area, leaf, stem and root biomass, and influence trichome abundance (Furness et al., 1999). Nitrogen has been shown to increase germination of C. officinale seeds (Freijsen et al., 1980). Svensson and Wigren (1982) showed application of fertilizer increased C. officinale dry biomass and second-year flowering by more than 100 and 50%, respectively, and also the number of flowers per plant.

Reproductive Biology

C. officinale reproduces by seeds, with mature plants producing 2000-4000 seeds (Powell et al., 1994). Seeds attached to the mother plant can remain viable for 2-3 years (Anon., 2002b) whereas buried seeds rarely remain viable for more than one year. Viability of freshly-harvested mature seeds may exceed 90% (Boorman and Fuller, 1984). C. officinale mortality has been estimated to be 75% from seed to seedlings, 77% from seedlings to rosettes, and 94% from rosettes to flowering (Boorman and Fuller, 1984). Less than 1% of C. officinale seeds survive to produce seeds, and the high seedling mortality was suggested to be due to moisture deficits early in the summer prior to deep root penetration. Repeated flowering has been reported to occur in some C. officinale plants in the second, third and even fourth year (Boorman and Fuller, 1984), suggesting that this weed is not strictly monocarpic. In the majority of cases, however, plants die after flowering. C. officinale flowers are perfect (Taylor and MacBryde, 1977) and seed production is via autogamy. Pollination does not require insects and outcrossing or vivipary have not been reported (Upadhyaya et al., 1988). The weed relies on innate, non-embryogenic seed dormancy for its persistence; impermeability of seed coats to oxygen has been suggested as the underlying mechanism of dormancy (Qi et al., 1993; Stabell, et al., 1998). C. officinale seeds contain a high level of phenolic substances and polyphenol oxidase activity and phenolics in C. officinale seeds exert an allelopathic influence on neighbouring species. Decoated seed leachate significantly inhibits seed germination and seedling growth of several species associated with C. officinale in nature.

Environmental Requirements

In Ontario, Canada, C. officinale infested regions have 770-1020 mm annual precipitation, 3.9-10.9°C mean January temperature and 19.2-22.2°C mean July temperature (Anon., 1982). Elsewhere in Canada, C. officinale inhabits zones with hot, dry summers and cold winters. C. officinale is common in areas with sandy and/or alkaline calcareous soils of variable fertility, also on gravelly and rocky sites. In Canada, C. officinale is associated with soils of Burnisolic, Luvisolic and Chernozemic orders in Alberta (Lodge et al., 1971) and is found on Eutric and Dystric Brunisolic, brown and dark brown Chernozemic and Luvisolic soils in British Columbia (Cranston and Pethybridge, 1986).

Associations

In British Columbia, Canada, C. officinale occurs mainly in the interior Douglas fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa)-bunchgrass biogeoclimatic zones (Taylor and MacBryde, 1977).

Soil Tolerances

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Soil drainage

  • free

Soil reaction

  • alkaline

Soil texture

  • light

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Ceutorhynchus cruciger Herbivore British Columbia

Notes on Natural Enemies

Top of page The insects Ceutorhynchus crucifer (Schroder, 1976) and C. trisignatus (Coleoptera) (Kallweit, 1977) have been recorded on C. officinale, as well as the fungal pathogens Botrytis cinerea and Erysiphe cichoracearum (Shaw, 1973), though their specificity and effects are not known. Two further insects Mogulones cruciger and Longitarsus quadriguttatus (Anon., 2002b) and two other fungal pathogens Erysiphe cynoglossi (Clerck-Floate, 1999; Clerck-Floate and Schwarzlander, 2002) and Phoma pomorum (Anon., 2002b) have been investigated as potential biological control agents.

Means of Movement and Dispersal

Top of page Natural Dispersal (Non-Biotic)

C. officinale nutlets remain attached to the mother plant after maturation for up to 3 years or more, forming an aerial seed bank. These seeds, however, do not disperse long distances naturally unless attached to animal fur, with Boorman and Fuller (1984) reporting that over 75% of C. officinale seeds fall within 1.2 m of the mother plants. A study in the Netherlands reported that most viable C. officinale seeds occur within the top 1 cm of the soil profile and seeds were not found at soil depths greater than 5 cm.

Vector Transmission (Biotic)

Nutlets disperse by attaching to the fur of animals, mostly cattle and sheep, grazing in infested areas (Upadhyaya et al., 1988; Upadhyaya and Cranston, 1991; Clerck-Floate, 1997).

Accidental Introduction

C. officinale seeds can also disperse as contaminants of crop seeds or soil, and the weed was probably introduced to North America as a contaminant in cereal seeds (Knight et al., 1984). It may also be transported internationally in wool or animal fur, or even attached to live introduced stock (Upadhyaya et al., 1988).

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Soil, sand and gravelseeds Yes

Plant Trade

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Plant parts not known to carry the pest in trade/transport
Leaves
True seeds (inc. grain)

Impact Summary

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

Impact

Top of page Due to its robust growth habit and deep root system, C. officinale reduces rangeland forage yield by competing for resources. It also interferes with establishment of desirable forage grasses, thereby decreasing forage availability for grazing and C. officinale itself is not a desirable food for animals. The barbed fruits of C. officinale attach to animal fur (Gains and Swan, 1972) which reduces their market value and may increase veterinary costs (Upadhyaya et al., 1988).

C. officinale is also a poisonous weed (Greatorex, 1966; Mandryka, 1979; Bartik and Piskac, 1981; Knight et al., 1984), with sheep being less susceptible than cattle or horses (Anon., 2002b). Its leaves contain the toxic alkaloids, echinatine, heliosupine and acetylheliosupine which are poisonous to animals when ingested (McGaw and Woolley, 1979; Resch and Mienwald, 1982; Knight et al., 1984); the concentration of these alkaloids is highest in rosette leaves. Fortunately, grazing animals will avoid browsing this species where alternative forage is available, but poisoning may occur when animals are fed hay contaminated with C. officinale leaves.

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Centrocercus minimus (Gunnison sage-grouse)USA ESA listing as threatened species USA ESA listing as threatened speciesColoradoEcosystem change / habitat alterationUS Fish and Wildlife Service, 2013

Social Impact

Top of page C. officinale has been reported to cause dermatitis when handled (Muenscher, 1939; Taylor and MacBryde, 1977).

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Highly adaptable to different environments
  • Highly mobile locally
  • Has high reproductive potential
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Negatively impacts agriculture
  • Negatively impacts human health
  • Negatively impacts animal health
  • Negatively impacts tourism
  • Reduced amenity values
Impact mechanisms
  • Competition - monopolizing resources
  • Produces spines, thorns or burrs
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult/costly to control

Uses

Top of page Root extracts of C. officinale have been reported to cure fever and chest and respiratory ailments (Cockayne, 1961; Altschul, 1973). Leaves of C. officinale have also been used as a mole repellent in gardens and for protection of stored vegetables and fruits from rodents (Bocs, 1983).

Uses List

Top of page

Medicinal, pharmaceutical

  • Traditional/folklore

Similarities to Other Species/Conditions

Top of page C. officinale rosettes can be confused with blueweed (Echium vulgare) but the latter is separable by its narrow, more harshly hairy rosette leaves and conspicuous blue flowers (Frankton and Mulligan, 1970) as compared to the reddish-purple flowers of C. officinale. It may also be confused with common mullein (Verbascum thapsus) though this species has rosette leaves that are more hairy and have less conspicuous venation than the rosette leaves of C. officinale.

Prevention and Control

Top of page Cultural Control

Svensson and Wigren (1982) reported that inter-specific competition significantly reduced dry biomass of first- and second-year C. officinale plants as well as seed production. Dispersal of nutlets by animals, humans, vehicles and equipment should be avoided (Anon., 2002b).

Mechanical Control

For small C. officinale populations and before seeds are formed, control by hand pulling is possible (Anon., 2002b). Cutting of young rosettes below the crown in autumn or early spring, mowing of flowering stems close to the ground, and ploughing followed by cultivation have been shown to control C. officinale (Muenscher, 1980). Dickerson and Fay (1982) showed that clipping of second-year plants during flowering reduced seed production significantly and seed production of plants that resumed growth declined dramatically; however, removal of leaves from second year plants neither affected seed number nor seed weight (Boorman and Fuller, 1984).

Chemical Control

Picloram, dicamba, chlorsulfuron (Cranston and Ralph, 1983; Cranston et al., 1983; Cranston and Pethybridge, 1986; Cranston and Wood, 1986) and 2,4-D amine (Dickerson and Fay, 1982) have been reported to effectively control C. officinale (Upadhyaya et al., 1988). In Montana, USA, seed production of second year C. officinale plants was most affected by 2,4-D when it was applied to plants 28 cm high (Dickerson and Fay, 1982), whereas chlorsulfuron provided complete control from the beginning of the rosette state until the bolted plants were 28 cm tall (Dickerson and Fay, 1982).

Biological Control

There are attempts to identify insects and pathogens for the biological control of C. officinale (Conner et al., 2000). Erysiphe cynoglossi, a powdery mildew fungus that is commonly found occurring on C. officinale, has been suggested as a potential biological control agent for this weed in North America (Clerck-Floate, 1999). The fungus, with characteristic white or grey velvety mycelium growth, is seen on all above-ground parts of C. officinale plants under field conditions. The fungus has been reported to reduce C. officinale root crown diameter, biomass, nutlet number, nutlet size, seed set and seed germination (Clerck-Floate, 1999) and the potential for use in biocontrol of C. officinale in North America is currently being investigated (Clerck-Floate, 1999, Clerck-Floate and Schwarzlander, 2002). A weevil, Mogulones cruciger, and a beetle, Longitarsus quadriguttatus, have also been studied for biocontrol of C. officinale (Anon., 2002b), both attacking the roots. M. cruciger was released in British Columbia, Canada, in 1998 and has shown promising results (Anon., 2002b). Phoma pomorum, an indigenous pathogen which causes brown lesions on the leaves has also been investigated (Anon., 2002b).

References

Top of page

Alex JF, Switzer CM, 1977. Ontario Weeds. Descriptions, Illustrations and Keys to their Identification. Ontario, Canada: Ministry of Agriculture and Food College, University of Guelph, Publication 505:200 pp.

Altschul S, 1973. Drugs and Foods from Little-known Plants. Cambridge, USA: Harvard University Press.

Anon., 1982. Canadian climate normals, temperature and precipitation, Ontario (1951-1980). Environment Canada, Atmospheric Environment Service, Government of Canada, 254 pp.

Anon., 2002. Guide to Weeds in British Columbia. Canada: British Columbia Ministry of Agriculture, Food and Fisheries Publication, 195 pp.

Anon., 2002. Seven Steps to Managing your Weeds. A Manual for Integrated Weed Management in British Columbia, Canada. British Columbia Ministry of Agriculture, Food and Fisheries Publication, 58 pp.

Bartic M, Piskac A, 1981. Veterinary Toxicology. Amsterdam, the Netherlands: Elsevier Scientific Publication Company.

Bocs A, 1983. Cynoglossum officinale against moles and rodents. Kerteszet es Szoleszet, 32:13.

Boivin B, 1966. Enumeration des plantes du Canada. IV. Herbidées, 2 partie: Connatae Nat. Can., 93:989-1063.

Boorman LA, 1982. Some plant growth patterns in relation to the sand dune habitat. Journal of Ecology, 70:607-614.

Boorman LA, Fuller RM, 1984. The comparative ecology of two sand dune biennials: Lactuca virosa L. and Cynoglossum officinale L. New Phytologist, 96:609-629.

Breitung AJ, 1957. Annonated catalogue of the vascular flora of Saskatchewan. American Midland Naturalist, 58:58-72.

Breitung AJ, 1957. Plants of Waterton Lakes National Park, Alberta. Canadian Field Naturalist, 71:39-71.

Britton DM, 1951. Cytogenetic studies on the Boraginaceae. Brittonia, 7:233-266.

Clapham AR, Tutin TG, Warburg EF, 1962. Flora of the British Isles. Second edition. Cambridge, UK: Cambridge University Press.

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