Allium triquetrum L.

Title: Allium triquetrum L.

Scientific Name:

Allium triquetrum L.

Common Names:

angled onion, three-cornered garlic, three-cornered leek

Source and more images (via ALA)

Habitat: Warm-temperate regions, usually on poorly drained heavier soils along watercourses (Parsons and Cuthbertson, 1992). It is a weed of urban areas, roadsides and pastures (Parsons and Cuthbertson, 1992). Angled onion invades dry coastal vegetation, lowland grassland and grassy woodland, dry sclerophyll forest and woodland, damp sclerophyll forest, wet sclerophyll forest, riparian vegetation and freshwater wetland (seasonal) (Carr et al., 1992).

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Seeds and bulbs germinate in autumn. (Parsons and Cuthbertson, 1992)

2. Establishment requirements? Occurs in woodlands and ‘shady places'. (Carr et al., 1992; Tutin et al., 1980)

3. How much disturbance is required? Establishes in minor disturbed ecosystems (e.g. riparian, wetlands & woodlands), and pastures. (Carr et al., 1992; Parsons and Cuthbertson, 2001)

GROWTH / COMPETITIVE

4. Life form? Bulbous perennial herb. Geophyte. (Parsons and Cuthbertson, 2001)

5. Allelopathic properties? None reported.

6. Tolerates herb pressure? Consumed - response unknown. However, probably recovers quickly as it is noted as being "a very persistent weed which may take some time and intensive effort to completely eradicate". (NCC, 1992).

7. Normal growth rate? Does not compete strongly with crops and improved pastures. Can completely smother and replace native ground cover vegetation. (NCC, 1992; Parsons and Cuthbertson, 1992)

8. Stress tolerance to frost, drought, w/logg, sal. etc? Tolerant of water logging (occurs on poorly drained soils along watercourses). Also, assumed tolerant of frosts (occurs on slopes of Great Dividing Range and the Dandenong Ranges). (Parsons and Cuthbertson, 1992)

REPRODUCTION

9. Reproductive system? Reproducing by seeds and bulbs. (Parsons and Cuthbertson, 2001)

10. Number of propagules produced? Probably < 50 seeds produced by each small bulb.
(See picture Hyde-Wyatt & Morris, 1980 and O'Neill, 1962).

11. Propagule longevity? ?

12. Reproductive period? Provides a complete ground cover in some areas.
- forms monocultures. (Parsons and Cuthbertson, 2001)

13. Time to reproductive maturity? Year one - Seeds germinate. Year two - Bulbs germinate. Year three - Seeds produced by bulbs. (Parsons and Cuthbertson, 2001)

DISPERSAL

14. Number of mechanisms? Agricultural produce, animals, machinery, vehicles, garden refuse and contaminated soil. Also insects and water. (NCC, 1992; Parsons and Cuthbertson, 2001)

15. How far do they disperse?

Impact Assessment

RECREATION

1. Restrict human access? Although invading a significant number of environmental vegetation formations, A. triquetrum, as a low growing perennial herb (to 50 cm high), is would have minimal impact on human access. (Carr et al., 1992; Muyt, 2001)

2. Reduce tourism? It is a persistent species capable of totally dominating ground flora. During leaf growth and flowering stage its presence is quite obvious resulting in a major negative impact on aesthetics. "The leaves and stems have a strong garlic-like aroma when crushed." Some recreational activities may be affected as a result. (Muyt, 2001)

3. Injurious to people? No known toxicity or harmful physical properties (burrs, spines, etc.). It has been used as a culinary herb. (Blood, 2001)

4. Damage to cultural sites? The obvious presence of the plant would produce a moderate negative visual effect. (Muyt, 2001)

ABIOTIC

5. Impact flow? Terrestrial species. (Parsons and Cuthbertson, 2001)

6. Impact water quality? Terrestrial species. (Parsons and Cuthbertson, 2001)

7. Increase soil erosion? Colonies dense, out-competes other herbaceous plants leaving bare ground in summer dormancy period, thereby increasing likelihood of erosion.” (Blood, 2001)

8. Reduce biomass? "Dense stands will smother and crowd out any competing ground-flora while seriously impeding over-storey regeneration." It is only active from mid-winter to early summer, thus leaving infested areas bare of vegetation for about six months of the year. Biomass would be decreased. (Muyt, 2001) ; Blood, 2001)

9. Change fire regime? Prefers moist environments. Dried plant material provides little fuel. Low probability of fire risk. (Muyt, 2001)

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC=Plains grassy woodland (E); CMA=West Gippsland; Bioreg=Highlands-Southern Fall; VH CLIMATE potential. "...tenacious, persistent species capable of totally dominating the ground-flora wherever conditions are suitable." Major displacement of dominant sp. within a layer. (Muyt, 2001)

10(b) Impact on medium value EVC? EVC=Herb-rich foothill forest (D); CMA=Corangamite; Bioreg=Central Victorian Uplands; VH CLIMATE potential. "...tenacious, persistent species capable of totally dominating the ground-flora wherever conditions are suitable." Major displacement of dominant sp. within a layer. (Muyt, 2001)

10(c) Impact on low value EVC? EVC=Heathy woodland (LC); CMA=West Gippsland; Bioreg=Gippsland Plain; VH CLIMATE potential. "...tenacious, persistent species capable of totally dominating the ground-flora wherever conditions are suitable." Major displacement of dominant sp. within a layer. (Muyt, 2001)

11. Impact on structure? Not known as a problem in environmental situations. It occurs in lowland grassland and grassy woodland vegetation, but its distribution is rare and it occurs in small populations. Minor effect on > 20% of the floral strata. (Muyt, 2001)

12. Effect on threatened flora?

FAUNA

13. Effect on threatened fauna?

14. Effect on non-threatened fauna? Its presence is widespread, in medium to large populations, and it invades a large number of vegetative forms. It is thus likely to have a major negative effect on the habitat of non-threatened fauna. (Carr et al., 1992; Blood, 2001)

15. Benefits fauna? "Attachments on seeds [are] attractive to ants, which are important vectors." Literature does not clarify native or introduces spp. (Blood, 2001)

16. Injurious to fauna? No toxic properties. Both humans and animals have eaten the plant. (Blood, 2001))

PEST ANIMAL

17. Food source to pests? "Attachments on seeds [are] attractive to ants, which are important vectors." Literature does not clarify native or introduced spp. Assume potential for both. (Blood, 2001)

18. Provides harbor? As a bulbous herb, the plant only has foliage for six months. It would not provide any suitable, permanent harbor. (Blood, 2001)

AGRICULTURE

19. Impact yield? A. triquetrum, "does not compete in strongly in crops and improved pastures." Little affect agricultural yield. (Parsons and Cuthbertson, 2001)

20. Impact quality? The plant, "imparts a strong onion flavour and an unpleasant odour to dairy products and meat, making them unfit for sale." Contaminates product making it unfit for sale. (Parsons and Cuthbertson, 2001)

21. Affect land values? Due to its significant impact on agricultural quality, the presence of A. triquetrum in paddocks would have a negative impact on land prices. However, the plant can be controlled with appropriate farm practices. (Parsons and Cuthbertson, 2001)

22. Change land use? The plant can be controlled with straightforward cultivation techniques and the use of incrop herbicide sprays. Access by grazing animals would be restricted until weed was eliminated. (Parsons and Cuthbertson, 2001)

23. Increase harvest costs? A known vector is contaminated mud on farm machinery and vehicles. Strict hygiene practices must be observed to prevent further spread. Potential to increase harvest costs through cleaning vehicles and machinery. (Blood, 2001)

24. Disease host/vector? None evident.

Feedback

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Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of an anonymous donor.

Attachments:

angled_onions.jpg
angled onion via ala.JPG
distribution_map (10).png

referenced by (3)

wra1036: Common Name - T (via three-cornered leek)wra1036: Common Name - T (via three-cornered garlic)wra702: Common Name - A (via angled onion)

Article: wra11 (permalink)
Categories: :wra:a, :wra:inv1, :wra:invmh, :wra:inv2, :wra:inv3, :wra:inv4, :wra:invml, :wra:inv5, :wra:invl, :wra:inv6, :wra:inv7, :wra:inv8, :wra:inv9, :wra:invh, :wra:inv10, :wra:inv11, :wra:invm, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impl, :wra:imp2, :wra:impmh, :wra:imp3, :wra:imp4, :wra:impml, :wra:imp5, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:impm, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imph, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 13 May 2009; 3:45:33 PM AEST

Author Name: David Low
Author ID: adminDavid