Climate Matching Map
| Attachment | Size |
|---|---|
| climatematch-arum_italicum-washington-20251101.pdf (1.15 MB) | 1.15 MB |
1. Question 1
Yes
1
Very High
Yes. Multiple escaped populations are reported fron both public and private lands in San Juan County (San Juan and Lopez Islands) and King County (Kirkland, Seattle, Vashon Island), Washington.
Board, Washington State Noxious Weed Control. 2014. “Written Findings of the Washington State Noxious Weed Control Board: Arum Italicum.”
2. Question 2
Yes
2
High
The climate match tool comparing GBIF distribution to Oregon climate shows coincidence in coastal Oregon and British Columbia and in Appalachian chain in eastern US. See Climate Match results.
No references cited.
3. Question 3
Yes
2
Very High
Yes. In Washington, Oregon, and California on the West Coast, and in 11 states in the eastern and southern US: New York, Maryland, Virginia, West Virginia, Indiana, Illinois, Missouri, North Carolina, Tennesee, Georgia, and Alabama.
Swearingen, J., and C. Bargeron. 2015. “Italian Arum: Invasive Plant Atlas of the United States”. http://www.invasiveplantatlas.org/subject.html?sub=13931.
4. Question 4
Yes
3
High
Invasive range in Oregon, California, New York, and southern Appalachians match climate of western Washington. http://websites.greeninfo.org/plantright/finder/ ; Climate Matching Results, ARIT.pdf
Swearingen, J., and C. Bargeron. 2015. “Italian Arum: Invasive Plant Atlas of the United States”. http://www.invasiveplantatlas.org/subject.html?sub=13931.
5. Question 5
Yes
1
High
The USDA Plants database does not report Arum maculatum, a closely related species, as invasive, or even introduced, anywhere in North America. However, GBIF records A. maculatum as invasive in Sweden and Denmark, both countries having areas of similar climate to Washington according to Plantright's PRE-combined climate match tool.
Service, USDA Natural Resource and Conservation. 2015. “PLANTS Database”. US Dept. of Agriculture, Natural Resource Conservation Service, Washington, D.C. https://plants.usda.gov/.
Secretariat, GBIF. 2016. “GBIF Backbone Taxonomy”. Copenhagen, Denmark: GBIF Secretariat. https://www.gbif.org/.
6. Question 6
No
0
High
A comparison of GBIF world distribution with Plantright's PRE-combined climate match tool shows more than half of Arum italicum's distribution is found beyond the climate match region for Washington.
Secretariat, GBIF. 2016. “GBIF Backbone Taxonomy”. Copenhagen, Denmark: GBIF Secretariat. https://www.gbif.org/.
7. Question 7
Yes
1
Very High
Accounts and photographs describe & show smothering infestations in San Juan and King Counties, Washington.
Board, Washington State Noxious Weed Control. 2014. “Written Findings of the Washington State Noxious Weed Control Board: Arum Italicum.”
8. Question 8
No
0
Low
No suggestion of fire influence in any of the literature reviewed.
No references cited.
9. Question 9
Yes
1
Low
All parts of the plant are toxic if ingested by humans or animals and is is avoided by grazing animals due to contact irritation to skin and mouths.
Board, Washington State Noxious Weed Control. 2014. “Written Findings of the Washington State Noxious Weed Control Board: Arum Italicum.”
Victoria, Agriculture. 2016. “Invasiveness Assessment - Italian Lily (Arum Italicum) in Victoria”. http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/invasive_it….
10. Question 10
No
0
Very High
Species is a low-growing forb generally < 40 cm.
Board, Washington State Noxious Weed Control. 2014. “Written Findings of the Washington State Noxious Weed Control Board: Arum Italicum.”
“Jepson EFlora: Arum Italicum”. 2017. http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=14303.
11. Question 11
Yes
1
Very High
The production of bulblets that become independent plants is well known in the species, as described in Mendez (1999) and in Mendez and Obeso (1993).
Méndez, M. and J. R. Obeso. 1993. Size-dependent reproductive and vegetative allocation in Arum italicum (Araceae). Canadian Journal of Botany 71: 309—314.
Méndez, M. and J. R. Obeso. 1993. Size-dependent reproductive and vegetative allocation in Arum italicum (Araceae). Canadian Journal of Botany 71: 309—314.
Mendez, M. (1999) 1999. “Effects of Sexual Reproduction on Growth and Vegetative Propagation in the Perennial Geophyte Arum Italicum (Araceae)”. Plant Biology 1: 115-20.
Mendez, M., and J. R. Obeso. 1993. “Size-Dependent Reproductive and Vegetative Allocation in Arum Italicum (Araceae)”. Canadian Journal of Botany 71: 309-14. doi:10.1139/b93-032.
12. Question 12
Yes
1
Very High
Plants routinely produce daughter tubers (bulblets) which break off and form new plants.
No references cited.
13. Question 13
Yes
1
Very High
Mendez and Obeso (1993) and Albre and Giberneau (2008) report that production of viable seed is a common reproductive strategy of this species.
Mendez, M., and J. R. Obeso. 1993. “Size-Dependent Reproductive and Vegetative Allocation in Arum Italicum (Araceae)”. Canadian Journal of Botany 71: 309-14. doi:10.1139/b93-032.
Albre, Jerome, and Marc Gibernau. 2008. “Reproductive Biology of Arum Italicum (Araceae) in the South of France”. Botanical Journal of the Linnean Society 156: 43-49. doi:10.1111/j.1095-8339.2007.00737.x.
14. Question 14
No
0
High
One study found an average seed production per inflorescence of 82.8 (Albre, Quilichini and Gibernau (2003). Most plants produce 2-4 inflorescences (Mendez and Diaz 2001); therefore the number of seeds produced is likely to be less than 1000.
Mendez, M., and A. Diaz. 2001. “Flowering Dynamics in Arum Italicum (Araceae): Relative Role of Inflorescence Traits, Flowering Synchrony, and Pollination Context on Fruit Initiation”. American Journal of Botany 88: 1774-80. http://www.amjbot.org/content/88/10/1774.
Albre, J, Angelique Quilichini, and Marc Gibernau. 2003. “Pollination Ecology of Arum Italicum (Araceae)”. Botanical Journal of the Linnean Society 141. Oxford University Press: 205-14.
15. Question 15
Yes
1
Very High
Diaz et al. (2006) tested germination of selfed and outcrossed seed of Arum italicum and found rates between 45-53%.
Diaz, Anita, Melanie Aka Amoin, and Marc Gibernau. 2006. “The Effectiveness of Some Mechanisms of Reproductive Isolation in Arum Maculatum and A. Italicum (Araceae)”. Biological Journal of the Linnean Society 150: 323-28. https://www.researchgate.net/publication/227683831_The_effectiveness_of….
16. Question 16
No
0
Medium
Viable seed is produced in 4-5 years according to Boyce (1993), cited in Agriculture Victoria (2020).
Boyce, P. 1993. The Genus Arum. A Kew Magazine Monograph. London: HMSO Publications Centre.
Victoria, Agriculture. 2016. “Invasiveness Assessment - Italian Lily (Arum Italicum) in Victoria”. http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/invasive_it….
17. Question 17
Yes
1
High
Blooms March-June (Calflora Taxon report 730)
Calflora. 2011. “Calflora: Arum Italicum”. https://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=730.
18. Question 18
Yes
1
High
Mendez and Obeso (1993) observed dispersal of fruits by birds. Washington State Noxious Weed Control Board (2014) also cites Boyce (1993) to this effect.
Mendez, M., and J. R. Obeso. 1993. “Size-Dependent Reproductive and Vegetative Allocation in Arum Italicum (Araceae)”. Canadian Journal of Botany 71: 309-14. doi:10.1139/b93-032.
Boyce, P. 1993. The Genus Arum. A Kew Magazine Monograph. London: HMSO Publications Centre.
Board, Washington State Noxious Weed Control. 2014. “Written Findings of the Washington State Noxious Weed Control Board: Arum Italicum.”
19. Question 19
No
0
Low
Evidence is lacking. Washington State Noxious Weed Control Board (2014) cited a New Zealand source (https://www.weedbusters.org.nz/what-are-weeds/weed-list/italian-arum/ , cited as weedbusters.co.nz]) for water dispersal, but neither source provides a primary source for the claim or mention of the frequency of its occurrence.
Board, Washington State Noxious Weed Control. 2014. “Written Findings of the Washington State Noxious Weed Control Board: Arum Italicum.”
20. Question 20
No
0
Low
None of the literature reviewed suggested this as an important mechanism.
No references cited.
Evaluation Notes
Added new climate match map and link but did not check whether new map affects answer to #6. Also made minor edits to references for new website. (J. Burger 11/1/2025)
Total PRE Score
17
20
79
