Arctotheca calendula (L.), fertile.  Levyns Family - Asteraceae. Common Names(s) - Capeweed, plain-treasure flower. Synonym(s) - Arctotis calendula L. (basionym) , Cryptostemma calendula (L.) Druce, Cryptostemma calendulacea R. Br., Venidium decurrens hort.

Answer

Score

1.01

Is the species highly domesticated?

y=-3, n=0

n

0

1.02

Has the species become naturalized where grown?

y=1, n=-1

1.03

Does the species have weedy races?

y=-1, n=-1

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

1

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

1

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

n

0

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

n

0

2.05

Does the species have a history of repeated introductions outside its natural range?

y=-2, ?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

y

1.5

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

y

3

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

y

3

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

y

1.5

4.01

Produces spines, thorns or burrs

y=1, n=0

n

0

4.02

Allelopathic

y=1, n=0

4.03

Parasitic

y=1, n=0

n

0

4.04

Unpalatable to grazing animals

y=1, n=-1

n

0

4.05

Toxic to animals

y=1, n=0

y

1

4.06

Host for recognized pests and pathogens

y=1, n=0

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

0

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

0

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

n

0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

1

4.11

Climbing or smothering growth habit

y=1, n=0

n

0

4.12

Forms dense thickets

y=1, n=0

y

1

5.01

Aquatic

y=5, n=0

n

0

5.02

Grass

y=1, n=0

n

0

5.03

Nitrogen fixing woody plant

y=1, n=0

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

y

1

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

0

6.02

Produces viable seed.

y=1, n=-1

y

1

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

y

1

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

1

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

1

1

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

y

1

7.02

Propagules dispersed intentionally by people

y=1, n=-1

n

-1

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

-1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

1

7.05

Propagules water dispersed

y=1, n=-1

7.06

Propagules bird dispersed

y=1, n=-1

y

1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

y

1

7.08

Propagules survive passage through the gut

y=1, n=-1

y

1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

y

1

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

y

1

8.03

Well controlled by herbicides

y=-1, n=1

n

1

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

1

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

24

Notes

Source

1.01

(1) No evidence.

(1) WRA Specialist.

1.02

N/A

1.03

N/A

2.01

(1) Native range: Lesotho; South Africa -Eastern Cape, KwaZulu-Natal, Northern Cape, Western Cape.

(1) 2011. USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network (GRIN) [Online Database Index]. National Germplasm Resources Laboratory, Beltsville, Maryland. http://www.ars-grin.gov/cgibin/ npgs/html/index.pl

2.02

(1) Native range: Lesotho; South Africa -Eastern Cape, KwaZulu-Natal, Northern Cape, Western Cape.

(1) 2011. USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network (GRIN) [Online Database Index]. National Germplasm Resources Laboratory, Beltsville, Maryland. http://www.ars-grin.gov/cgibin/ npgs/html/index.pl

2.03

(1) USDA Hardiness Zones:9-11.

(1) 2002. MacKenzie. Perennial ground covers. Timber Press, http://books.google.com/books?id=u2MYhwxcVyc
C&pg=PA73&lpg=PA73&dq=arctotheca+calendula+%2B+%22soil%22&source=bl&ots=4xHUkwpR
u8&sig=_OzPHAiFczTRWdx07UTSD_T5kI&hl=en&ei=BhS_TZPLIzTiAKF95wp&sa=X&oi=b

2.04

(1) Capeweed has naturalized in central Portugal and southwestern Spain (Codex Plantarum Vascularium Mediterraneum, 2000), southern Portugal, Australia, New Zealand,

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

2.05

(1) Capeweed has naturalized in central Portugal and southwestern Spain (Codex Plantarum Vascularium Mediterraneum, 2000), southern Portugal, Australia, New Zealand,

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

3.01

(1) Capeweed has naturalized in central Portugal and southwestern Spain (Codex Plantarum Vascularium Mediterraneum, 2000), southern Portugal, Australia, New Zealand,

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

3.02

(1) Capeweed is a troublesome, widespread weed in Tasmanian pastures, crops, home gardens and disturbed sites like building sites and roadsides. [scored 3.04 environmental weed]

(1) 2011. Tamar Valley Weed Strategy. Tamar Valley Weed Strategy - Arctotheca calendula.www.weeds.asn.au

3.03

(1) Capeweed is a weed of alfalfa in Australia and canola, especially in Eastern Australia. In a field survey of weeds in 86 cereal crops in southern New South Wales, Australia, capeweed was the most widespread species . Capeweed was estimated to cost Australia 9.7 million (5.8 million US dollars) per annum in yield losses from residual weeds in annual winter crops including wheat, oats, barley, canola, pulses, and lupins, not counting pre and post emergent control costs. Capeweed often dominates pastures in Australia.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

3.04

(1) In Western Australia, cape weed is increasing rapidly in the arid zone. In many of the inland pastoral stations that had massive stands of many genera and species of annual everlastings, capeweed is replacing the everlastings. Invasion by A. calendula is described as a serious threat to five types of vegetation formations in Victoria (dry coastal vegetation, heathland & healthy woodland, mallee shrubland, lowland grassland & grassy woodland, dry sclerophyll forest & woodland.

(1) 1992. Carr, G.W./Yugovic, J.V./Robinson, K.E..Environmental weed invasions in Victoria conservation and management implications. Department of Conservation and Environment,

3.05

(1) Arctotheca populifolia is an environmental weed in Victoria.

(1) 1992. Carr, G.W./Yugovic, J.V./Robinson, K.E..Environmental weed invasions in Victoria conservation and management implications. Department of Conservation and Environment,

4.01

(1) Stems: creeping or decumbent, originating from an individual rosette; succulent, hairy (tomentose), and ribbed; stems creep along or just below the soil surface, bearing fully formed leaves and reaching lengths of up to nine feet in one growing season. Leaves: pinnately lobed, 2-10 in (5-25 cm) long, upper surface finely hairy (cobwebby), lower surface densely hairy or silky (white-woolly).

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

4.02

(1) Unknown.

(1) WRA Specialist.

4.03

(1) Asteraceae.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

4.04

(1) Although stock will eat Capeweed, it is of lower nutritional value than many good pastures. Plants die off after flowering decreasing the food supply available to stock and leaving bare patches that allow more invasive weeds to establish.

(1) 2011. Tamar Valley Weed Strategy. Tamar Valley Weed Strategy - Arctotheca calendula.www.weeds.asn.au

4.05

(1) Stock have died from nitrate poisoning after grazing on Capeweed growing on highly fertile soils. Milk from dairy cows feeding on the weed can have tainted milk. Horses and donkeys can have allergic skin reactions to the pollen encountered as they graze on the plant.

(1) 2011. Tamar Valley Weed Strategy. Tamar Valley Weed Strategy - Arctotheca calendula.www.weeds.asn.au

4.06

(1) Unknown.

(1) WRA Specialist.

4.07

(1) No evidence. (2) No evidence.

(1) 2011. National Center for Biotechnology Information. PubMed. U.S. National Library of Medicine, Bethesda, Maryland http://www.ncbi.nlm.nih.gov/ (2) 2011. Specialized Information Services, U.S. National Library of Medicine. TOXNET toxicology data network [online database]. National Institutes of Health, http://toxnet.nlm.nih.gov/

4.08

(1) No evidence.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

4.09

(1) Grows best in full sun to light shade. (2) Full sun.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication (2) 2002. MacKenzie. Perennial ground covers. Timber Press, http://books.google.com/books?id=u2MYhwxcVycC&pg=PA73&lpg=PA73&dq=arctotheca+calendula+
%2B+%22soil%22&source=bl&ots=4xHUkwpRu8&sig=_OzPHAiFczTRWdx07UTSD_T5kI&hl=en&ei=
BhS_TZPLIzTiAKF95wp&sa=X&oi=b

4.10

(1) Tolerates a wide range of soil types. (2) Adaptable to various well-drained soils.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

4.11

(1) "Stems: creeping or decumbent, originating from an individual rosette; succulent, hairy (tomentose), and ribbed; stems creep along or just below the soil surface, bearing fully formed leaves and reaching lengths of up to nine feet in one growing season.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

4.12

(1) "Capeweed grows over and displaces other herbs and in coastal grasslands and riparian zones forms monospecific stands of impenetrable mats up to several thousand square feet. It is a rapidly growing groundcover, and, if planted on one-foot centers, will establish full cover within six months ). Capeweed is an aggressive competitor for water and space, and it seriously threatens native plant communities by crowding out grasses, herbs, and small shrubs. Once capeweed is established, it is difficult for other plants, particularly perennials, to become established."

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

5.01

(1) Terrestrial

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

5.02

(1) Asteraceae.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

5.03

(1) Herbaceous.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

5.04

(1) Capeweed can form small tubers 1 cm thick and 3 cm long. Plants can be spread when tubers and stem pieces with nodes are moved from location to location by heavy equipment used for routine grading, resurfacing, or fill removal.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

6.01

(1) No evidence.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication

6.02

(1) Capeweed reproduces by seed and creeping stolons, rooting at nodes. One plant can spread to cover up to 200 square feet in one to two years

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

6.03

(1) Unknown.

(1) WRA Specialist.

6.04

(1) 1989. Powles, S.B./Tucker, E.S.. A capeweed (Arctotheca calendula) biotype in Australia resistant to Bipyridyl herbicides. Weed Science.37: 60-62.

(1) This study on herbicide resistance in Arctotheca calendula states that there are biotypes of this species resistant to the herbicide. [Biotypes are groups of organisms having the same genotype. A genotype is created by apomixis].

6.05

(1) A potential beneficial effect of capeweed is that it provides a food source for larvae of the Painted Lady butterfly. Bee keepers regard capeweed as an important source of pollen.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

6.06

(1) Capeweed reproduces by seed and creeping stolons, rooting at nodes. One plant can spread to cover up to 200 square feet in one to two years

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

6.07

(1) The period between seed sowing and flowering was 149-157 days. The interval between first flower and shedding of the first seed varied from 32 days early in the season, to 15 days later in the season, as temperatures increased.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

7.01

(1) Capeweed dispersal is predominantly by wind or in contaminated soil. Seeds and rooted stolons also spread aided by human activity and animals . While no direct evidence is available that capeweed achenes survive the passage through an animal’s digestive tracts, many plant propagules do. Achenes may become lodged in fur.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

7.02

(1) Although capeweed is mentioned in references such as Perennials for American Gardens as “useful for covering slopes and other open areas”, capeweed is not widely available in the U.S. nursery trade. The Anderson Horticultural Library’s Source Guide identified no sources, and an Internet search detected only one U.S. site, a mention by eLandscape in their plant library (http://www.elandscape.com). McKeown Inc., a landscape design firm that links to the eLandscape plant dictionary, has never sold the plant, nor offers it for sale.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

7.03

(1) No evidence.

(1) WRA Specialist.

7.04

(1) Capeweed dispersal is predominantly by wind or in contaminated soil. Seeds and rooted stolons also spread aided by human activity and animals . While no direct evidence is available that capeweed achenes survive the passage through an animal’s digestive tracts, many plant propagules do. Achenes may become lodged in fur.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

7.05

(1) Unknown.

(1) WRA Specialist

7.06

(1) Seeds are spread by birds and animals, and as a contaminant in soils on vehicles and machinery.

(1) 2011. Tamar Valley Weed Strategy. Tamar Valley Weed Strategy - Arctotheca calendula.www.weeds.asn.au

7.07

(1) Seeds are spread by birds and animals, and as a contaminant in soils on vehicles and machinery.

(1) 2011. Tamar Valley Weed Strategy. Tamar Valley Weed Strategy - Arctotheca calendula.www.weeds.asn.au

7.08

(1) Seeds are spread by birds and animals, and as a contaminant in soils on vehicles and machinery.

(1) 2011. Tamar Valley Weed Strategy. Tamar Valley Weed Strategy - Arctotheca calendula.www.weeds.asn.au

8.01

(1) In an Australian experiment, capeweed plants produced about 4330 seeds per plant with no treatment applied. With fifty percent of their leaves and most of the buds and flowers removed at late flowering (simulating heavily grazed vegetation), capeweed still produced more than 2400 seeds per plant. These results may partially explain observed increases of capeweed under heavy grazing pressure, as seed setting by other species may be reduced by severe defoliation.

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

8.02

(1) Capeweed seeds are dormant at harvest. Subsequent ageing, exposure to light and growth regulators promote germination of capeweed seeds. Tillage during seed-bed preparation inverts the soil, stimulating germination of buried capeweed seeds that are brought to the surface (Chaharsoghi and Jacobs, 1998). Ecotypes have evolved differences in their seed dormancy, enabling adaptation to particular environments

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

8.03

(1) "Herbicide application to large, dense capeweed patches can be successful in reducing the density of the infestation. Repeated application of 3 percent glyphosate may be needed to permanently eliminate capeweed. Glyphosate has been recommended for use on the related fertile capeweed. However, ten years of continual herbicide use on the fertile capeweed in Australia resulted in aherbicide-resistant biotype."

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

8.04

(1) Capeweed can form small tubers 1 cm thick and 3 cm long. Plants can be spread when tubers and stem pieces with nodes are moved from location to location by heavy equipment used for routine grading, resurfacing, or fill removal

(1) Lehtonen, P. 2009. Weed risk assessment for Arctotheca calendual (L.) Levyns capewee. United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine Biological and Technical Services. Riverdale, Maryland.

8.05

(1) Capeweed is not known to be eaten by California wildlife or invertebrates and has no known pathogens in the central coast region of California. No effective biological control agents have been reported. (2) Unknown.

(1) 2000. Alvarez, M.. Arctotheca calendula. University of California Press, Berkeley http://www.calipc. org/ip/management/ipcw/pages/detailreport.cfm@usernumber=7&surveynumber=182.php?print [Accessed 2011 May 2](2) Wra Specialist Personal communication