Pacific Island Ecosystems at Risk (PIER)


Strophanthus amboensis


RISK ASSESSMENT RESULTS: Evaluate, score: 2


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment

Strophanthus amboensis (Schinz) Engl. & Pax Family - Apocynaceae. Common Names(s) - . Synonym(s) - .

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

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

n

0

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

1

2.05

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

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

n

0

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

0

3.03

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

n=0

n

0

3.04

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

n=0

n

0

3.05

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

n=0

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

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

y

1

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

4.10

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

y

1

4.12

Forms dense thickets

y=1, n=0

n

0

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

n

0

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

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

6.07

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

See left

7.01

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

y=1, n=-1

n

-1

7.02

Propagules dispersed intentionally by people

y=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

n

-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

-1

7.08

Propagules survive passage through the gut

y=1, n=-1

n

-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

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

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

(1)No evidence

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

1.02

1.03

2.01

(1)A glabrous liana from Angola.

(1)Omino, E. 2001. Apocynaceae (part 1). CRC Press. Boca Raton, FL.

2.02

(1)A glabrous liana from Angola.

(1)Omino, E. 2001. Apocynaceae (part 1). CRC Press. Boca Raton, FL.

2.03

(1)A glabrous liana from Angola.

(1)Omino, E. 2001. Apocynaceae (part 1). CRC Press. Boca Raton, FL.

2.04

(1)A glabrous liana from Angola.

(1)Omino, E. 2001. Apocynaceae (part 1). CRC Press. Boca Raton, FL.

2.05

(1)No evidence

(1)http://www.hear.org/gcw/species/strophanthus_speciosus/ [Accessed 15 Dec 2008]

3.01

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinames.htm [Accessed 15 Dec 2008]

3.02

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinames.htm [Accessed 15 Dec 2008]

3.03

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinames.htm [Accessed 15 Dec 2008]

3.04

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinames.htm [Accessed 15 Dec 2008]

3.05

(1)Strophanthus speciosus listed as a weed [no other information on or evidence of impacts was found]

(1)http://www.hear.org/gcw/species/strophanthus_speciosus/ [Accessed 15 Dec 2008]

4.01

(1)No evidence. Deciduous, densely intertwined shrub or liana, with thick, snake-like stems. LEAVES simple, with successive pairs at right-angles to each other; broadly ovate, 20–50 mm long; pale green; midrib prominent and sparsely downy below.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.02

Unknown

4.03

(1)No evidence

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.04

(1)GENERAL The seeds contain glucosides and, due to the presence of strophanthin, the plant is lethal if browsed. The plant is used medicinally. Due to its lovely flowers, this plant has horticultural potential. [probably unpalatable to animals, but no evidence found]

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.05

(1)GENERAL The seeds contain glucosides and, due to the presence of strophanthin, the plant is lethal if browsed. The plant is used medicinally. Due to its lovely flowers, this plant has horticultural potential.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.06

Unknown

4.07

(1)Strophanthus is one of the widest spread, best documented, most traded, and most rapidly working poisons.

(1)Yaniv, Z. and U. Bachrach. 2005. Handbook of Medicinal Plants. Haworth Press. Binghamton, NY.

4.08

(1)Deciduous, densely intertwined shrub or liana, with thick, snake-like stems [fire ecology unknown]

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.09

(1)Sun Exposure: Sun to Partial Shade Light Shade [shade tolerance of related Strophanthus preussii, no information found on S. amboensis]

(1)http://davesgarden.com/guides/pf/go/60444/ [Accessed 15 Dec 2008]

4.10

(1)HABITAT Mainly found on rocky outcrops, hill slopes, kloofs and cliffs, but on sandy plains in eastern Caprivi [probably tolerates many soil types given habitat conditions]

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.11

(1)Deciduous, densely intertwined shrub or liana, with thick, snake-like stems.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

4.12

(1)Uncommon in scattered localities in the north-west and on the north-central plateau, with new records from the Karstveld (specimen MU575, UIR1) and eastern Caprivi

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

5.01

(1)Terrestrial

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

5.02

(1)Apocynaceae

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

5.03

(1)Apocynaceae

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

5.04

(1)Deciduous, densely intertwined shrub or liana, with thick, snake-like stems.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

6.01

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

6.02

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

6.03

Unknown

6.04

Unknown

6.05

(1)FLOWERS corolla tube short, red; corolla lobes narrow, up to 40 mm long, twisted, yellow. [floral structure does not suggest requirements for specialist pollinators]

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

6.06

Unknown

6.07

Unknown

7.01

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end [seeds adapted for wind dispersal and not for attachment to dispersal agent]. (2)Another interesting find was Strophanthus amboensis, a clambering shrub with shiny green, distinctly opposite leaves, and large opposite pairs of follicles. The leaves are folded along the midrib. When ripe, the follicles burst open to release a cloud of silky parachutes with tiny dark seeds attached. The flowers are yellow star-shaped with five long thin petals.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008] (2)Hoffmann, L. 2004. BOTSOC NEWS JULY 2004. Botanical Society of Namibia. http://www.biodiversity.org.na/biosyst/society/botsoc/BotsocNews-04-07.htm [Accessed 15 Dec 2008]

7.02

7.03

(1)No evidence that plant is grown with produce

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

7.04

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end. (2)Another interesting find was Strophanthus amboensis, a clambering shrub with shiny green, distinctly opposite leaves, and large opposite pairs of follicles. The leaves are folded along the midrib. When ripe, the follicles burst open to release a cloud of silky parachutes with tiny dark seeds attached. The flowers are yellow star-shaped with five long thin petals.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008] (2)Hoffmann, L. 2004. BOTSOC NEWS JULY 2004. Botanical Society of Namibia. http://www.biodiversity.org.na/biosyst/society/botsoc/BotsocNews-04-07.htm [Accessed 15 Dec 2008]

7.05

(1)Strophanthus amboensis (Schinz) Engl. & Pax occurs in the gallery forests along the Kunene River. Its leaves suggest a near relationship to Strophanthus grandiflorus. [distribution along river suggests seeds or pods may float]

(1)Gerstner, J. 1949. THE ARROW-POISON STROPHANTHUS IN SOUTHERN AFRICA. S.A. MEDICAL JOURNAL 14 May 1949: 390.

7.06

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008]

7.07

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end [seeds adapted for wind dispersal and not for attachment to dispersal agent]. (2)Another interesting find was Strophanthus amboensis, a clambering shrub with shiny green, distinctly opposite leaves, and large opposite pairs of follicles. The leaves are folded along the midrib. When ripe, the follicles burst open to release a cloud of silky parachutes with tiny dark seeds attached. The flowers are yellow star-shaped with five long thin petals.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008] (2)Hoffmann, L. 2004. BOTSOC NEWS JULY 2004. Botanical Society of Namibia. http://www.biodiversity.org.na/biosyst/society/botsoc/BotsocNews-04-07.htm [Accessed 15 Dec 2008]

7.08

(1)FRUIT two dry, woody capsules, each 200–300 mm long, cylindrical, woody; splitting open when ripe. SEEDS many, with a tuft of silky hairs on one end [seeds not adapted for internal animal dispersal] (2)Another interesting find was Strophanthus amboensis, a clambering shrub with shiny green, distinctly opposite leaves, and large opposite pairs of follicles. The leaves are folded along the midrib. When ripe, the follicles burst open to release a cloud of silky parachutes with tiny dark seeds attached. The flowers are yellow star-shaped with five long thin petals.

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008] (2)Hoffmann, L. 2004. BOTSOC NEWS JULY 2004. Botanical Society of Namibia. http://www.biodiversity.org.na/biosyst/society/botsoc/BotsocNews-04-07.htm [Accessed 15 Dec 2008]

8.01

(1)Seed quantities unknown

(1)www.biodiversity.org.na/treeatlas/SpPDFs/Sp538.pdf [Accessed 12 Dec 2008] (2)Hoffmann, L. 2004. BOTSOC NEWS JULY 2004. Botanical Society of Namibia. http://www.biodiversity.org.na/biosyst/society/botsoc/BotsocNews-04-07.htm [Accessed 15 Dec 2008]

8.02

(1)The seed of Strophanthus is not difficult to germinate. At temperatures of 72 to 75 degrees F. and humidity of 85%o, almost complete germination can be expected from fresh seed. How long the seed will remain viable is not known at present, but tests at Glenn Dale show that when stored under calcium chloride at a temperature of 65 degrees F. the seed remains viable at least eight months [no evidence found from field conditions]

(1)Creech, J.L. and R. F. Dowdle. 1952. Propagation of Strophanthus. Economic Botany 6(1): 48-54.

8.03

Unknown

8.04

Unknown

8.05

Unknown


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