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

Pilea microphylla; rockweed

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

y

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

n

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

y

3.02

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

n=0

y

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

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

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

y=1, n=0

y

4.1

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

y=1, n=0

y

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

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

1

7.01

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

y=1, n=-1

n

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

y

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

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

y

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:

6

Source

Notes

1.01

no evidence

1.02

McConnell, J.; Muniappan, R. (1991) Introduced ornamental plants that have become weeds on Guam. Micronesia, 1991, No.3, Supplement, pp.47-49, 4 ref.

AB: Introduced ornamental plants that are considered weeds on Guam include Antgonon leptopus, Spathodea campanulata, Coccinea grandis, Bauhinia monandra, Clerodendrum quadriloculare, Lantana camara, Ficus spp., Asystasia gangetica, Pilea microphylla, Wedelia trilobata, Mikania scandens and Mimosa pudica. Characteristics of ornamental plants that could become weeds on Guam include rapid growth/regrowth and prolific seed production.

1.03

no evidence

2.01

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?101575 (02 October 2002)

Distributional range:
Native:
Northern America: Mexico; United States - Florida [s. & on keys]
Southern America: Antigua and Barbuda; Bahamas; Belize; Bolivia; Brazil; Colombia; Costa Rica; Cuba; Dominica; Ecuador; El Salvador; French Guiana; Grenada; Guadeloupe; Guatemala; Guyana; Hispaniola; Honduras; Jamaica; Martinique; Montserrat; Nicaragua; Panama; Peru; Puerto Rico; St. Lucia; St. Vincent and Grenadines; Suriname; Venezuela
Other: naturalized elsewhere

2.02

2.03

(1)http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF (2)http://www.mrec.ifas.ufl.edu/Foliage/orn/orn1_11.htm

(1)USDA hardiness zones: 10B through 11 (2)thrives under the humid conditions typical of many nursery areas.

2.04

USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?101575 (02 October 2002)

Distributional range:
Native:
Northern America: Mexico; United States - Florida [s. & on keys]
Southern America: Antigua and Barbuda; Bahamas; Belize; Bolivia; Brazil; Colombia; Costa Rica; Cuba; Dominica; Ecuador; El Salvador; French Guiana; Grenada; Guadeloupe; Guatemala; Guyana; Hispaniola; Honduras; Jamaica; Martinique; Montserrat; Nicaragua; Panama; Peru; Puerto Rico; St. Lucia; St. Vincent and Grenadines; Suriname; Venezuela
Other: naturalized elsewhere

2.05

(1) Reddy, C. S.; Raju, V. S. (2001) Additions to the weed flora of Andhra Pradesh, India. Journal of Economic and Taxonomic Botany, 2002, Vol.26, No.1, pp.195-198, 1 ref.
(2) McConnell, J.; Muniappan, R. (1991) Introduced ornamental plants that have become weeds on Guam. Micronesia, 1991, No.3, Supplement, pp.47-49, 4 ref.
(3) Galera, H.; Ratyska, H. (1999) Greenhouse weeds in the botanical garden of Pas in Warsaw-Powsin. Acta Societatis Botanicorum Poloniae, 1999, Vol.68, No.3, pp.227-236, 30 ref.

(1) India, (2) Guam, (3) Poland

3.01

McConnell, J.; Muniappan, R. (1991) Introduced ornamental plants that have become weeds on Guam. Micronesia, 1991, No.3, Supplement, pp.47-49, 4 ref.

AB: Introduced ornamental plants that are considered weeds on Guam include Antgonon leptopus, Spathodea campanulata, Coccinea grandis, Bauhinia monandra, Clerodendrum quadriloculare, Lantana camara, Ficus spp., Asystasia gangetica, Pilea microphylla, Wedelia trilobata, Mikania scandens and Mimosa pudica. Characteristics of ornamental plants that could become weeds on Guam include rapid growth/regrowth and prolific seed production.

3.02

Reddy, C. S.; Raju, V. S. (2001) Additions to the weed flora of Andhra Pradesh, India. Journal of Economic and Taxonomic Botany, 2002, Vol.26, No.1, pp.195-198, 1 ref.

AB: Seven species of Magnoliopsida are reported from Andhra Pradesh as naturalized alien weeds of gardens (Chamaesyce hyssopifolia and Phyllanthus tenellus of Euphorbiaceae, Peperomia pellucida of Piperaceae, Pilea microphylla of Urticaceae, and Talinum triangulare of Portulacaceae), cultivated fields (Heliotropium subulatum of Boraginaceae), and railway tracks (Eryngium foetidum of Apiaceae).

3.03

no evidence

3.04

http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF

potentially invasive

3.05

Bacon, P., P.J. Terry, N. Waltham, & P.Castro S. (1997) An Electronic Atlas of World Weed and Invasive Plants. Version 1.0, 1997. A database based on the original work "A Geographical Atlas of World Weeds" by Holm et al 1979.

P. nummulariaefolia was listed as a principal weed in Trinidad.

4.01

Whistler, A.W. (1995) Wayside Plants of The Islands. Isle Botanica, Honolulu. 202pp. p.136

no description of these traits

4.02

no evidence

4.03

no evidence

4.04

no evidence

4.05

http://www.moggies.co.uk/nontoxix.html

non-toxic to cats

4.06

no evidence

4.07

no evidence

4.08

http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF

succulent plant.

4.09

(1)Dehgan, B. (1998) Landscape Plants for Subtropical Climates. University Press of Florida., Gainesville, FL. 638pp. p.573 (2)http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF

(1)"A popular ground cover for moist , shady locations." (2)Light requirement: plant grows in part shade/part sun; plant grows in the shade

4.1

(1)Dehgan, B. (1998) Landscape Plants for Subtropical Climates. University Press of Florida., Gainesville, FL. 638pp. p.573 (2)http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF

(1)"Tolerates a wide range of both light and soil types, but does best in shady moist locations." (2)Soil tolerances: extended flooding; alkaline; clay; sand; acidic; loam

4.11

small herb

4.12

no evidence

5.01

terrestrial

5.02

Urtricaceae, herb

5.03

herb

5.04

no evidence

6.01

no evidence

6.02

Pilea microphylla. A web page of University of isconsin Botanical Garden. Avaiable at: <http://www.botany.wisc.edu/Garden/Urticaceae/Pilea_microphylla.html>

"Propagation: Stem cutting, Seed ."

6.03

no evidence

6.04

Dehgan, B. (1998) Landscape Plants for Subtropical Climates. University Press of Florida., Gainesville, FL. 638pp. p.573

"monoecious."

6.05

http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF

forcefully-ejected pollen from the rather inconspicuous flowers

6.06

Whistler, A.W. (1995) Wayside Plants of The Islands. Isle Botanica, Honolulu. 202pp. p.136

"rooting from the nodes." [does not spread much via nodes]

6.07

Whistler, A.W. (1995) Wayside Plants of The Islands. Isle Botanica, Honolulu. 202pp. p.136

"Prostrate annual or short-lived herb."

7.01

no evidence

7.02

Blessington, T. M.; Collins, P. C. (1993) Foliage plants: prolonging quality: postproduction care and handling. Foliage plants: prolonging quality: postproduction care and handling., 1993, 203 pp.

AB: Methods for prolonging the longevity and retaining the quality of foliage pot plants by growers, wholesalers, shippers, retailers and consumers are discussed. Specific recommendations are given for 60 foliage plant subjects. []including P. microphylla.]

7.03

Galera, H.; Ratyska, H. (1999) Greenhouse weeds in the botanical garden of Pas in Warsaw-Powsin. Acta Societatis Botanicorum Poloniae, 1999, Vol.68, No.3, pp.227-236, 30 ref.

AB: "Systematic studies carried out in the greenhouses of the Botanical Garden in Warsaw-Powsin, Poland, from 1992-95 revealed that the flora of weeds was very species rich. A total of 243 taxa of vascular plants and 17 species of bryophytes were recorded and lists of these species are presented. Native plants (89 species), greenhouse-escapes (87 species) and permanently established aliens (48 species) co-dominated in the garden. In addition, 10 species of garden-escapes, i.e. plants cultivated in the immediate neighbourhood of the greenhouses, were recorded indoors. Noteworthy were two species (Ruellia caroliniensis and Pilea microphylla ) that had been brought accidentally to the glasshouses together with plant material - this group of plants is least numerous, but quite frequent in the study area. "

7.04

(1)Whistler, A.W. (1995) Wayside Plants of The Islands. Isle Botanica, Honolulu. 202pp. p.136 (2)http://hort.ifas.ufl.edu/shrubs/PILMICA.PDF

(1)"Fruit an ellipsoid achene 0.5-1 mm long, with a single seed that is ejected from the ripen fruit." (2)Fruit cover: dry or hard

7.05

no evidence

7.06

no evidence

7.07

no evidence

7.08

no evidence of consumption

8.01

Whistler, A.W. (1995) Wayside Plants of The Islands. Isle Botanica, Honolulu. 202pp. p.136

"Fruit an ellipsoid achene 0.5-1 mm long, with a single seed that is ejected fro the ripen fruit."

8.02

8.03

http://edis.ifas.ufl.edu/EH139

he plants were sprayed with one of six herbicide solutions: Barricade 65WG, Gallery 75DF, Image 1.5EC, Premier 1.2EC, Ronstar 50WP and Roundup. All herbicide solutions and a check solution contained a surfactant and were prepared and applied following label instructions.
Best control was obtained from Ronstar 50WP. Artillery plants growing in full sun or 60% shade were almost dead two weeks after Ronstar was applied and no new growth had appeared eight weeks after plants were sprayed.

8.04

http://edis.ifas.ufl.edu/EH139

does not tolerate foot traffic

8.05

no evidence