Verbesina encelioides
(golden crownbeard)

Pictures

Picture	Title	Caption	Copyright
Title Invasive habit Caption Verbesina encelioides (golden crown-beard); invasive habit in Laysan albatross colony. Eastern Island, Midway Atoll. June 05, 2008 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Invasive habit	Verbesina encelioides (golden crown-beard); invasive habit in Laysan albatross colony. Eastern Island, Midway Atoll. June 05, 2008	©Forest Starr & Kim Starr - CC BY 4.0
Title Habit Caption Verbesina encelioides (golden crown-beard); habit on sand dunes. North Beach Sand Island, Midway Atoll. June 10, 2008 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Habit	Verbesina encelioides (golden crown-beard); habit on sand dunes. North Beach Sand Island, Midway Atoll. June 10, 2008	©Forest Starr & Kim Starr - CC BY 4.0
Title Invasive habit Caption Verbesina encelioides (golden crown-beard); invasive habit, filling crater at Manana, Oahu. February 25, 2005 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Invasive habit	Verbesina encelioides (golden crown-beard); invasive habit, filling crater at Manana, Oahu. February 25, 2005	©Forest Starr & Kim Starr - CC BY 4.0
Title Flowers and foliage Caption Verbesina encelioides (golden crown-beard); flowers and foliage. Runway overrun fields, Sand Island, Midway Atoll. June 02, 2008 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Flowers and foliage	Verbesina encelioides (golden crown-beard); flowers and foliage. Runway overrun fields, Sand Island, Midway Atoll. June 02, 2008	©Forest Starr & Kim Starr - CC BY 4.0
Title Flower Caption Verbesina encelioides (golden crown-beard); close-up of flower. Paia, Maui. April 16, 2006 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Flower	Verbesina encelioides (golden crown-beard); close-up of flower. Paia, Maui. April 16, 2006	©Forest Starr & Kim Starr - CC BY 4.0
Title Seedhead Caption Verbesina encelioides (golden crown-beard); seedhead. Cargo pier, Sand Island, Midway Atoll. June 13, 2008 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Seedhead	Verbesina encelioides (golden crown-beard); seedhead. Cargo pier, Sand Island, Midway Atoll. June 13, 2008	©Forest Starr & Kim Starr - CC BY 4.0
Title Small plants Caption Verbesina encelioides (golden crown-beard); small plants. Spit Island, Midway Atoll. June 03, 2008 Copyright ©Forest Starr & Kim Starr - CC BY 4.0	Small plants	Verbesina encelioides (golden crown-beard); small plants. Spit Island, Midway Atoll. June 03, 2008	©Forest Starr & Kim Starr - CC BY 4.0

Identity

Preferred Scientific Name

• Verbesina encelioides (Cav.) Benth. & Hook.f. ex A.Gray

Preferred Common Name

• golden crownbeard

Other Scientific Names

• Verbesina exauriculata (B.L. Rob. & Greenm.) Cockerell
• Ximenesia encelioides Cav.

International Common Names

• English: butter daisy; crownbeard; crown-beard; golden crown-beard; South African daisy; wild sunflower
• Spanish: flor de Santa Maria; girasolcito del campo; girasolillo; yuyo de Santa Maria

Local Common Names

• Argentina: quellocisa; queluzisa
• Germany: Verbesine, Goldgelbe
• USA: American dogweed
• USA/Texas: cowpen daisy

EPPO code

• VEEEN (Verbesina encelioides)

Summary of Invasiveness

V. encelioides is a native annual herb in the USA and Mexico, but there exists controversy as to its native status in South America. It has expanded its range into Europe, Asia, Africa and Australia. Cause and timing of initial introductions are mostly unknown. It is considered invasive in the northern Hawaiian Islands due to the displacement of native plant species and the negative impacts it has on breeding colonies of marine birds. It is a dominant invasive on Midway Atoll (PIER, 2013). V. encelioides also invades agricultural crops, especially peanuts, in the United States, Argentina, Australia and India, where allelopathy may provide interference. When grazed upon by livestock (sheep and cattle), animals become lethargic or may die due to the toxin galegine in the plant.

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Asterales
•                         Family: Asteraceae
•                             Genus: Verbesina
•                                 Species: Verbesina encelioides

Description

V. encelioides is an annual herb growing up to 150 cm high. Stems are densely short-hairy with mostly alternate leaves. Stems are 20-100 cm long. Leaf blades are lanceolate to triangular-ovate, bases broadly cuneate to truncate, dull green, 3-veined, with a coarsely dentate margin, and strigose-canescent hairs. The peduncle is subtended by leaf-like bracts. The inflorescence has 1-many heads with 1-2 phyllary series, 6-10 mm, and linear-lanceolate to linear. Chaff scales 6 to 8 mm and abruptly acuminate. Ray flowers are orange-yellow and disk flowers are yellow to light brown. Disk achenes are 4 to 6.5 mm, obovate, flattened, and with wide wing (Baldwin et al., 2012).

Plant Type

Distribution

Several sources indicate V. encelioides is native to the southwestern USA, Mexico and South America (Shluker, 1999; Carr, 2012). However, native origins within particular states in the USA, as well as in South America, are questioned (Coleman, 1974). USDA-ARS (2013) includes most of the USA and Mexico in its native range, and USDA-NRCS (2013) includes states as east as Florida and as north as Michigan in its native range. In South America the majority of herbarium collections are from Argentina (GBIF, 2012). See Schluker (1999) for a detailed discussion.

V. encelioides ssp. encelioides has a native range in the eastern and lowland USA (eastern Oklahoma and eastern Texas) and lowland northeastern Mexico, and prefers mesic climates, whereas V. encelioides ssp. exauriculata has a native range in the southwestern USA and into northwestern Mexico, and prefers more arid climates at higher elevations (Coleman, 1966, 1974).

Distribution Table

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.

Risk of Introduction

V. encelioides is able to invade various new habitats as the species has evolved in highly diverse ecosystems (Coleman, 1966, 1974). Seed germination in highly variable and in some cases nutrient-poor soil has also enabled the success and naturalization of V. encelioides into new habitats.

V. encelioides is currently cultivated in the Czech Republic (Euro+Med, 2012) and has been transported between Hawaiian islands, most likely on the tyres of vehicles (Shluker, 1999). Although negative environmental impacts have been reported once V. encelioides has naturalized on Hawaiian islands, the species has not been classified as a state noxious weed. Purposeful introductions have not been reported, but this should not be ruled out as the species does produce showy displays of flowers and has been cultivated, both as an ornamental and for its medicinal qualities (Jain et al., 2008).

Habitat

V. encelioies can be found in a variety of habitats, from riparian to coastal to upland to island. The preferred habitat is tropical to subtropical, with disturbed porous sandy soils and an open canopy (McCoy, 1987). The plant is also found along roads. The species does well on alkaline soils. Habitats with high shade or with very fine soil texture are not optimal sites for this species (Kaul and Mangal, 1987). It may become more invasive on fertile soils; it has been observed to have robust growth when associated with nesting marine birds, and poor growth when on islands with poor soils (Shluker, 1999).

In Hawaii, PIER (2013) reported it as ‘relatively common in dry, disturbed sites, 0-2,805 m’ in altitude.

V. encelioides ssp. encelioides prefers mesic climates, whereas V. encelioides ssp. exauriculata has prefers more arid climates at higher elevations (Coleman, 1966, 1974).

Habitat List

Host Plants and Other Plants Affected

Biology and Ecology

Genetics

n = 17 (Keil and Stuessy, 1977).

Reproductive Biology

Rapid uptake of water leads to germination and rapid plant growth, where flowering and seed production appear limited only by seasonal drought. Larger and heavier seeds have the highest germination rates and are maintained by plants growing in open and sand dune habitats. Although seeds were found to germinate over a wide range of soil moistures (11.3 to 34.8% with >50% germination rate) and temperatures (5 to 20ºC), drought and waterlogged soils suppressed germination. The optimal soil moisture for seed germination was 21% (Kaul and Mangal, 1987). This species is also both self- and cross-pollinated and very fecund, producing ample winged seeds for local dispersal (Kaul and Mangal, 1987).

In its exotic range of northern India, seed germination occurred in February, flowering started in March and the first fruit set started in May, lasting until December. In India V. encelioides emerges after the first cyclonic precipitation and it flourishes in both the hot and humid and cool seasons (Kaul and Mangal, 1987).

Physiology and Phenology

In India, V. encelioides grows well on many soil types and exhibits high phenotypic plasticity and ecological variability (Kaul and Mangal, 1987).

Longevity

V. encelioides is an annual herb.

Environmental Requirements

V. encelioides is considered drought tolerant. It grows best in the 800-900 mm annual rainfall. It is not tolerant to salinity or to shade and requires exposure to light to establish. V. encelioides is adapted to fine or medium textured soil (EPPO, 2013).

Climate

Latitude/Altitude Ranges

Air Temperature

Rainfall

Rainfall Regime

Soil Tolerances

Soil drainage

• free

Soil reaction

• alkaline
• neutral

Soil texture

• light

Natural enemies

Notes on Natural Enemies

The beetle Zygogramma bicolorata was observed attacking V. encelioides in Australia (Withers, 1998, in Anonymous, 2011).

Means of Movement and Dispersal

Natural Dispersal (Non-Biotic)

V. encelioides spreads by seed, which are dispersed by the wind.

Vector Transmission (Biotic)

V. encelioides may potentially be dispersed by birds.

Accidental Introduction

Transport of this species is most likely accidental, via contaminated soils on vehicle tyres, bulldozer treads or shoes.

Intentional Introduction

None reported, but it V. encelioides has been used in horticulture and for medicinal purposes. There is potential for accidental or purposeful introductions occurring from horticultural or medicinal activities.

Pathway Causes

Pathway Vectors

Impact Summary

Economic Impact

V. encelioides can directly impact agriculture, through competition with crops like peanuts in the USA, as well as poisoning livestock, including cattle and sheep in both the USA but more so in Argentina. Competitive experiments have shown that 3.2 V. encelioides weeds per metre row can decrease peanut harvest by 50% (Farris and Murray, 2006). One mechanism facilitating this interference success may be allelopathy (Inderjit et al., 1999). Toxicity in livestock has been linked to galegine, a chemical which causes dullness and anorexia at low doses and death at high doses when ingested in a single meal (Oelrichs and Vallely, 1981; Keeler et al., 1986; Keeler et al., 1992; Lopez et al., 1996; Jain et al., 2008).

V. encelioides is a known host to thrips (Frankliniella spp.), which are potential vectors of tomato spotted wilt virus. However, there are no studies linking V. encelioides to increases in tomato spotted wilt virus in cultivated crops (Mitchell and Smith, 1996).

Environmental Impact

Impact on Habitats

V. encelioides has proven most problematic to natural systems when invading oceanic islands (e.g. the Hawaiian islands). V. encelioides is invasive and problematic on the northwestern Hawaiian islands where it can form monotypic stands on sandy, coastal soils. By displacing native vegetation and disrupting the nesting behaviour of marine birds, this weed has transformed certain islands, like Midway Atoll and Kure Atoll, to the disadvantage of native wildlife (Shluker, 1999). Scaveola sericea (naupaka) and Ipomea pescaprae (beach morning glory) have been suggested as impacted native plant species.

V. encelioides is also widespread in India but there is no mention of how it is impacting native vegetation there. Kaul and Mangal (1987) stated that it creates dense pure stands in landscapes where native vegetation is naturally scarce.

There is very little or no research on the impact V. encelioides has on carbon pools, nutrient cycling or microorganism populations.

Impact on Biodiversity

V. encelioides has impacted the nesting activities of some marine birds (laysan albatross Phoebastria immutabilis, blackfoot albatross Phoebastria nigripes, Christmas shearwater Puffinus nativitatis and wedge-tailed shearwaters Puffinus pacificus) by trapping hatchling and young birds in its intertwining branches in the northwest Hawaiian islands.

Threatened Species

Risk and Impact Factors

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Pioneering in disturbed areas
• Fast growing
• Has high reproductive potential

• Ecosystem change/ habitat alteration
• Monoculture formation
• Negatively impacts agriculture
• Negatively impacts human health
• Threat to/ loss of native species
• Negatively impacts animal/plant collections
• Damages animal/plant products

• Competition - monopolizing resources
• Poisoning
• Rapid growth

Uses

Economic Value

Its economic and social benefits are limited, but V. encelioides is a horticultural species and has been used as a medicinal plant among certain native American peoples, and is being scrutinized for potential commercial medicinal value.

Environmental Services

V. encelioides provides pollen, nectar and seeds to insects and birds. It is unknown how this species affects nutrient cycling, carbon pools, soil biota and community ecology.

Uses List

General

• Ritual uses

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical

Detection and Inspection

One obvious character found on V. encelioides achenes are wings which can be used for identification (Coleman, 1966, 1974; Baldwin et al., 2012). For a description of the species with images refer to Feenstra and Clements (2008).

Similarities to Other Species/Conditions

This large annual shrub appears from a distance to resemble similar shrub-forming species in Asteraceae, as in the genus Encelia. In contrast to Encelia, V. encelioides has an unpleasant odor and its stems are densely short-hairy with mostly alternate leaves.

Prevention and Control

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.

V. encelioides has proven most problematic to natural systems when invading oceanic islands (e.g. the Hawaiian islands). Prevention of spread should be focused on between and within-island transportation via vehicle translocation. Cleaning soil from potentially contaminated vehicles or shoes will decrease the likelihood of transport. Purposeful transport for propagation will be by seed.

Infestations are associated with disturbed soils. In these areas management should focus on controlling the spread of known populations with whole-plant removal by manual or chemical means. Eradication should be the goal where feasible, as environmental and sensitive species impacts have been linked to this species.

When found as an agricultural weed, or in pasture, this species should be removed in the same manner as other annual weeds are managed, through physical/mechanical control or chemical control. The rapid germination and robust growth of this species likely precludes the effectiveness of cultural control. Biological control is not currently being explored.

Gaps in Knowledge/Research Needs

There appears to be a lack of basic and phenologic research conducted on V. encelioides in its native range. This work is needed to assess how it has adjusted to its naturalized range. It appears to be a very plastic species, able to survive and thrive in highly variable systems. The mechanisms and genes that contribute to this adaptive response to novel environments are unknown. The degree of plasticity and rapid evolution responsible for local adaptation is also unknown. Knowledge of these aspects of V. encelioides may aid genetics-based attempts to improve agriculture in arid regions.

References

Anonymous, 2011. Environmental Evaluation for the Release of the Biological Agent Zygogramma (Zygogramma bicolorata L.) to Control the invasive weed Parthenium (Parthenium hysterophorus L.) in Ethiopia. http://www.epa.gov.et/Download/EIA%20Documents%20for%20Review%20Comments/Environmental%20Evaluation%20for%20the%20Release%20of%20the%20Biological%20Agent%20Zyagogramma.pdf

Arellano A, 1997. Herbal medicine in northern New Mexico. Topeka, Kansas, USA: Herbs for Health, 46-52

Baldwin BG, Goldman DH, Keil DJ, Patterson R, Rasatti TJ, Wilken DH, 2012. The Jepson manual: vascular plants of California. Berkeley, California, USA: University of California Press

Carr GD, 2012. Manoa campus plants. Hawaii, USA: University of Hawaii. http://www.botany.hawaii.edu/Faculty/Carr/page25

Coleman JR, 1966. A taxonomic revision of section Ximenesia of the genus Verbesina L. (Compositae). A taxonomic revision of section Ximenesia of the genus Verbesina, 76:475-481

Coleman JR, 1974. Verbesina section Ximenesia (Compositae): biosystematics and adaptive variation. Verbesina section Ximenesia (Compositae), 61:25-35

Council of Heads of Australasian Herbaria (CHAH), 2012. Australia's Virtual Herbarium. http://avh.ala.org.au

Dafni A, Heller D, 1982. Adventive flora of Isreal - phylogeographical, ecological and agricultural aspects. Adventive flora of Isreal, 140:1-18

EPPO, 2013. European and Mediterranean Plant Protection Organization. EPPO (online). Paris, France. http://www.eppo.int/

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

Euro+Med, 2012. Euro+Med PlantBase: The information resource for Euro-Mediterranean plant diversity. Palermo, Italy: University of Palermo. http://ww2.bgbm.org/EuroPlusMed

Everist SI, 1957. Common weeds of farms and pastures [ed. by Tucker, A. H.]. Brisbane, Australia: Government Printer

Farris RL, Murray DS, 2006. Influence of crownbeard (Verbesina encelioides) densities on peanut (Arachis hypogaea) yield. Weed Technology, 20(3):627-632

Feenstra KR, Clements DR, 2008. Biology and impacts of Pacific island invasive species. 4. Verbesina encelioides, golden crownbeard (Magnoliopsida: Asteraceae). Pacific Science, 62(2):161-176

GBIF, 2012. Global Biodiversity Information Facility. Global Biodiversity Information Facility (GBIF). http://data.gbif.org

Holm LG, Pancho JV, Herberger JP, Plucknett DL, 1979. A geographical atlas of world weeds. New York, USA: John Wiley and Sons, 391 pp

Inderjit, Asakawa C, Dakshini KMM, 1999. Allelopathic potential of Verbesina encelioides root leachate in soil. Canadian Journal of Botany, 77(10):1419-1424

Jain SC, Jain R, Singh R, Menghani E, 2008. Verbesina encelioides: perspective and potentials of a noxious weed. Indian Journal of Traditional Knowledge, 7(3):511-513

Kaul MLH, Mangal PD, 1987. Phenology and germination of crownbeard (Verbesina encelioides). Weed Science, 36(4):513-518

Keeler RF, Baker DC, Panter KE, 1992. Concentration of galegine in Verbesina encelioides and Galega officinalis and the toxic and pathological effects induced by the plants. Journal of environmental pathology, toxicology and oncology, 11:2, 11 pp

Keeler RF, Johnson AE, Stuart LD, Evans JO, 1986. Toxicosis from and possible adaptation to Galega officinalis in sheep and the relationship to Verbesina encelioides toxicosis. Veterinary and Human Toxicology, 28(4):309-315

Keil DJ, Stuessy TF, 1977. Chromosome counts of Compositae from Mexico and the United States. American Journal of Botany, 64(6):791-798

Lopez TA, Campero CM, Chayer R, Cosentino B, Caracino M, 1996. Experimental toxicity of Verbesina encelioides in sheep and isolation of galegine. Veterinary and Human Toxicology, 38(6):417-419

McCoy D, 1987. Oklahoma wildflowers. Oklahoma City, Oklahoma, USA: Ebsco Graphics

Mitchell FL, Smith JW Jr, 1996. Influence of Verbesina encelioides (Asterales: Asteraceae) on thrips (Thysanoptera: Terebrantia) populations and tomato spotted wilt virus epidemics in south Texas peanut fields. Journal of Economic Entomology, 89(6):1593-1600

Oelrichs P, Vallely P, 1981. Isolation of galegine from Verbesina encelioides, 44:754-755

Osten VA, Walker SR, Storrie A, Widderick M, Moylan P, Robinson GR, Galea K, 2007. Survey of weed flora and management relative to cropping practices in the north-eastern grain region of Australia. Australian Journal of Experimental Agriculture, 47(1):57-70. http://www.publish.csiro.au/nid/72.htm

PIER, 2013. Pacific Islands Ecosystems at Risk. Honolulu, Hawaii, USA: HEAR, University of Hawaii. http://www.hear.org/pier/index.html

Shluker A, 1999. HNIS Report for Verbesina encelioides

Turner BL, Bacon L, Urbatsch L, Simpson B, 1979. Chromosome numbers of South American Compositae, 66:173-178

Tutin TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM, Webb DA, 1976. Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae). Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae). Cambridge, UK: Cambridge University Press., 505 pp

USDA-ARS, 2013. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

USDA-NRCS, 2012. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

USDA-NRCS, 2013. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

Walther M, 2004. A guide to Hawaii's coastal plants. Honolulu, Hawaii, USA: Mutual Publishing, 144 pp

Witt, A., Luke, Q., 2017. Guide to the naturalized and invasive plants of Eastern Africa, [ed. by Witt, A., Luke, Q.]. Wallingford, UK: CABI.vi + 601 pp. http://www.cabi.org/cabebooks/ebook/20173158959 doi:10.1079/9781786392145.0000

Woodward P, 1972. The natural history of Kure Atoll, northwestern Hawaiian islands:164

Zayed KM, El-Karemy AR, 1989. Vegetation between Taif and El-Shafa highland (Asir mountains, Saudi Arabia). Vegetation between Taif and El-Shafa highland, 100(11-12):661-672

Distribution References

Anon, 1976. Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae). In: Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae). [ed. by Tutin T G, Heywood V H, Burges N A, Moore D M, Valentine D H, Walters S M, Webb D A]. Cambridge, UK: Cambridge University Press. 505 pp.

CABI, Undated. Compendium record. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

Carr GD, 2012. Manoa campus plants., Hawaii, USA: University of Hawaii. http://www.botany.hawaii.edu/Faculty/Carr/page25

Coleman JR, 1966. A taxonomic revision of section Ximenesia of the genus Verbesina L. (Compositae). In: A taxonomic revision of section Ximenesia of the genus Verbesina, 76 475-481.

Dafni A, Heller D, 1982. Adventive flora of Isreal - phylogeographical, ecological and agricultural aspects. In: Adventive flora of Isreal, 140 1-18.

EPPO, 2020. EPPO Global database. In: EPPO Global database, Paris, France: EPPO.

Euro+Med, 2012. Euro+Med PlantBase: The information resource for Euro-Mediterranean plant diversity., Palermo, Italy: University of Palermo. http://ww2.bgbm.org/EuroPlusMed

Everist SI, 1957. Common weeds of farms and pastures., [ed. by Tucker AH]. Brisbane, Australia: Government Printer.

Feenstra K R, Clements D R, 2008. Biology and impacts of Pacific island invasive species. 4. Verbesina encelioides, golden crownbeard (Magnoliopsida: Asteraceae). Pacific Science. 62 (2), 161-176. http://www.uhpress.hawaii.edu/journals DOI:10.2984/1534-6188(2008)62[161:BAIOPI]2.0.CO;2

GBIF, 2012. Global Biodiversity Information Facility. http://www.gbif.org/species

Holm L, Pancho J V, Herberger J P, Plucknett D L, 1979. A geographical atlas of world weeds. New York, Chichester (), Brisbane, Toronto, UK: John Wiley and Sons. xlix + 391 pp.

Inderjit, Asakawa C, Dakshini K M M, 1999. Allelopathic potential of Verbesina encelioides root leachate in soil. Canadian Journal of Botany. 77 (10), 1419-1424. DOI:10.1139/cjb-77-10-1419

Kaul M L H, Mangal P D, 1987. Phenology and germination of crownbeard (Verbesina encelioides). Weed Science. 36 (4), 513-518.

Keeler R F, Johnson A E, Stuart L D, Evans J O, 1986. Toxicosis from and possible adaptation to Galega officinalis in sheep and the relationship to Verbesina encelioides toxicosis. Veterinary and Human Toxicology. 28 (4), 309-315.

Lopez T A, Campero C M, Chayer R, Cosentino B, Caracino M, 1996. Experimental toxicity of Verbesina encelioides in sheep and isolation of galegine. Veterinary and Human Toxicology. 38 (6), 417-419.

Oelrichs P, Vallely P, 1981. Isolation of galegine from Verbesina encelioides., 44 754-755.

Osten V A, Walker S R, Storrie A, Widderick M, Moylan P, Robinson G R, Galea K, 2007. Survey of weed flora and management relative to cropping practices in the north-eastern grain region of Australia. Australian Journal of Experimental Agriculture. 47 (1), 57-70. http://www.publish.csiro.au/nid/72.htm DOI:10.1071/EA05141

PIER, 2013. Pacific Islands Ecosystems at Risk., Honolulu, Hawaii, USA: HEAR, University of Hawaii. http://www.hear.org/pier/index.html

Shluker A, 1999. HNIS Report for Verbesina encelioides.,

USDA-NRCS, 2012. The PLANTS Database. Greensboro, North Carolina, USA: National Plant Data Team. https://plants.sc.egov.usda.gov

Walther M, 2004. A guide to Hawaii's coastal plants., Honolulu, Hawaii, USA: Mutual Publishing. 144 pp.

Witt A, Luke Q, 2017. Guide to the naturalized and invasive plants of Eastern Africa. [ed. by Witt A, Luke Q]. Wallingford, UK: CABI. vi + 601 pp. http://www.cabi.org/cabebooks/ebook/20173158959 DOI:10.1079/9781786392145.0000

Zayed KM, El-Karemy AR, 1989. Vegetation between Taif and El-Shafa highland (Asir mountains, Saudi Arabia). In: Vegetation between Taif and El-Shafa highland, 100 (11-12) 661-672.

Links to Websites

Contributors

22/10/2012 Original text by:

Kai Palenscar, Consultant, USA

Distribution Maps