Pacific Island Ecosystems at Risk (PIER)


Euphorbia leucocephala


RISK ASSESSMENT RESULTS: Low risk, score: -2


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.

Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Euphorbia leucocephala (Common name: Pascuita, Snows of Kilimanjaro, Snowflakes, little christmas flower, white Poinsettia)

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

n

1.03

Does the species have weedy races?

y=-1, n=-1

n

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

2

2.02

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

2

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

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

n

3.02

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

n=0

n

3.03

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

n=0

n

3.04

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

n=0

n

3.05

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

n=0

y

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

n

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

n

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

y

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

4.09

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

y=1, n=0

4.1

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

y=1, n=0

n

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

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

y=1, n=0

n

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

n

6.07

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

See left

3

7.01

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

y=1, n=-1

y

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

7.05

Propagules water dispersed

y=1, n=-1

n

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

7.08

Propagules survive passage through the gut

y=1, n=-1

n

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

8.02

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

y=1, n=-1

8.03

Well controlled by herbicides

y=-1, n=1

8.04

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

y=1, n=-1

y

8.05

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

y=-1, n=1

Total score:

-2

Supporting data:

Notes

Source

1.01

No evidence

1.02

No evidence

1.03

No evidence

2.01

This native of Central America, from southern Mexico to El Salvador, can grow to 3 m tall.

http://www.rbgsyd.gov.au/sydney_gardens_domain/
gardens_feature/blooming_calendar/sydney_blooming_template29

2.02

(1) Climate: Will grow in Sydney and Perth and areas north but not in frost zones. In cooler areas it is worth a try in a sheltered north-facing position. (2)Introduced to Hawaii. (3)Widely cultivated

(1)http://www.burkesbackyard.com.au/1998/archives/26/
in_the_garden/flowering_plants_and_shrubs/euphorbia_leucocephala_snow_flake (2)http://www.hear.org/starr/hiplants/images/thumbnails/html/euphorbia_leucocephala_thumbnails.htm (3)Whistler, W.A. 2000. Tropical Ornamentals. Timber press, Portland, OR.

2.03

(1)Specimens from 50-1500 m but many were from cultivated plants (2)drought tolerant

(1)http://mobot.mobot.org/cgi-bin/search_vast (20http://www.fairchildtropicalgarden.com/blooms/mid-winter98.html

2.04

This native of Central America, from southern Mexico to El Salvador, can grow to 3 m tall.

http://www.rbgsyd.gov.au/sydney_gardens_domain/gardens_feature/blooming_calendar/sydney_blooming_template29

2.05

(1)cultivated elsewhere (2)Introduced to Hawaii.

(1)http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl?Euphorbia+leucocephala+ (2)http://www.hear.org/starr/hiplants/images/thumbnails/html/euphorbia_leucocephala_thumbnails.htm

3.01

No evidence

3.02

No evidence

3.03

No evidence

3.04

No evidence

3.05

E. helioscopia, E. heterophylla and E. hirta are listed as principal weeds in several countries.

Holm et al. 1997. An electronic atlas of weeds and invasive species. Version 1. CD-ROM database.

4.01

No evidence of such structures.

4.02

No evidence

4.03

No evidence

4.04

Don’t know

4.05

No evidence

4.06

This site does not list any fungi species to be associated with E. leucocephala.

http://nt.ars-grin.gov/fungaldatabases/all/FindRecOneFungusFrame.cfm

4.07

(1)Every part of the plant exudes a milky-white latex when damaged and may cause skin irritation when touched. (2)Caution - wear gloves when pruning and ensure no milky sap touches the body as it may be very irritating. (3)Toxic part: Latex.

(1)http://www.abc.net.au/gardening/stories/s780945.htm (2)http://www.abc.net.au/gardening/stories/s780945.htm (3)http://translate.google.com/translate?hl=en&sl=pt&u=http://
www.herbario.com.br/dataherb10/1612pot13.htm&prev=/search%3Fq%3D
Euphorbia%2Bleucocephala%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DG

4.08

(1)'Flowers in autumn and winter, from April to July and then loses its leaves for a short period. From spring it is green for the rest of the year.' (2)drought tolerant [could be a hazard if it grew at high densities in dry thickets]

(1)http://www.burkesbackyard.com.au/1998/archives/26/
in_the_garden/flowering_plants_and_shrubs/euphorbia_leucocephala_snow_flake?
mysource_site_extension=printer_friendly_pages (2)http://www.fairchildtropicalgarden.com/blooms/mid-winter98.html

4.09

(1)full sun to semi-shade (2)drought tolerant and thrives in full sun (3)full sun

(1)http://www.burkesbackyard.com.au/1998/archives/26/
in_the_garden/flowering_plants_and_shrubs/euphorbia_leucocephala_snow_flake?
mysource_site_extension=printer_friendly_pages (2)http://www.fairchildtropicalgarden.com/blooms/mid-winter98.html (3)http://www.rareflora.com/euphorbialeu.htm

4.1

Rich, well-drained soil.

http://www.abc.net.au/gardening/stories/s780945.htm

4.11

A tree

http://www.abc.net.au/gardening/stories/s780945.htm

4.12

No evidence

5.01

It is a fast growing, relatively large shrub.

http://www.abc.net.au/gardening/stories/s780945.htm

5.02

Euphorbiaceae

5.03

Euphorbiaceae

5.04

No evidence

6.01

No evidence

6.02

(1)Seeds for sale (2)Sprouting seeds used in experiment.

(1)http://translate.google.com/translate?hl=en&sl=fr&u=http://
www.baobabs.com/Euphorbia%2520leucocephala.htm&prev=/
search%3Fq%3DEuphorbia%2Bleucocephala%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DG (2)http://www.icess.ucsb.edu/~tiho/laticifers.pdf

6.03

no evidence

6.04

no evidence

6.05

produces masses of fragrant little flowers with glistening white bracts [suggests fly pollination syndrome]

http://www.fairchildtropicalgarden.org/horticulture/membersday03-sale.html

6.06

No evidence

6.07

It is a fast growing, relatively large shrub. [minimum estimate]

http://www.abc.net.au/gardening/stories/s780945.htm

7.01

Potted flowering plants are given as Christmas gifts [seeds dispersed unintentionally through gifts]

7.02

Euphorbia leucocephala 'Snow Flake' is a classic low maintenance plant that would suit the average garden.

http://www.burkesbackyard.com.au/1998/archives/26/in_the_garden/
flowering_plants_and_shrubs/euphorbia_leucocephala_snow_flake

7.03

No evidence

7.04

As with all Euphorbias, mature seed is released explosively. [no seed adaptations for wind]

http://www.abc.net.au/gardening/stories/s780945.htm

7.05

As with all Euphorbias, mature seed is released explosively.

http://www.abc.net.au/gardening/stories/s780945.htm

7.06

As with all Euphorbias, mature seed is released explosively.

http://www.abc.net.au/gardening/stories/s780945.htm

7.07

As with all Euphorbias, mature seed is released explosively.

http://www.abc.net.au/gardening/stories/s780945.htm

7.08

As with all Euphorbias, mature seed is released explosively.

http://www.abc.net.au/gardening/stories/s780945.htm

8.01

Fruit a 3-lobed schizocarp [3 seeds]

Whistler, W.A. 2000. Tropical Ornamentals. Timber Press, Portland, OR

8.02

No evidence regarding seedbank.

8.03

No evidence that the species is being controlled for.

8.04

(1) Likes heavy pruning after leaf drop and another light clip in early summer (2)The plant gains with being cut, even severely folded back after flowering.

(1)http://www.burkesbackyard.com.au/1998/archives/26/
in_the_garden/flowering_plants_and_shrubs/euphorbia_leucocephala_
snow_flake?mysource_site_extension=printer_friendly_pages (2)http://translate.google.com/translate?hl=en&sl=fr&u=http://
www.barbadine.com/pages/euphorbia_leucocephala_lie.htm&prev=/
search%3Fq%3DEuphorbia%2Bleucocephala%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DG

8.05

Don’t know


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