Doublegee (Emex spinosa)
Present distribution
|  This weed is not known to be naturalised in Victoria | ||||
| Habitat: Sandy shores, disturbed ground, elevation 0-500 m (FNA undated). Sand. Road verges, wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990). Emex spinosa grows in pasture (Jackson 2004). Sandy shores, disturbed ground, perennial crops, grasslands (Fed Noxious Weeds undated). In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is less wide-spread [than Emex australis] and, at this stage is most commonly found in parts of the Eyre Peninsula (Fromm 1996). | |||||
Potential distribution
Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries
| Map Overlays Used Land Use: Broadacre cropping; forestry; horticulture perennial; horticulture seasonal; pasture dryland; pasture irrigation Ecological Vegetation Divisions Coastal; heathland; basalt grassland; alluvial plains grassland Colours indicate possibility of Emex spinosa infesting these areas. In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable. | 
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Impact
QUESTION | COMMENTS | RATING | CONFIDENCE |
| Social |  | | |
| 1. Restrict human access? | E. spinosa is very similar to E. australis but with fruits and spines half the size. It has a more upright habit than E. australis. (Parsons and Cuthberston 2001). Emex spinosa is an erect, annual herb, up to 40 cm tall. E. spinosa has been found growing with E. australis in Australia. It has the potential to become a serious weed (like E. australis). It also spiny fruits (Scher undated). Small burrs (Jackson 2004). Spiny fruits/burrs may cause problems with access. Low nuisance value, impedes individual access; unable to walk to waterways. | ML | M |
| 2. Reduce tourism? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Small burrs (Jackson 2004). Not common in tourist areas. Minor effects to aesthetics and/or recreational uses. | ML | MH |
| 3. Injurious to people? | Small burrs (Jackson 2004). E. spinosa is very similar to E. australis but with fruits and spines half the size. It has a more upright habit than E. australis. ‘Spines [of Emex australis] cause discomfort and inconvenience to humans, particularly when barefooted’ (Parsons and Cuthbertson 2001). Spines, burrs or toxic properties at most times of the year. | MH | M |
| 4. Damage to cultural sites? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Little or negligible impacts on aesthetics or structure of site. | L | MH |
| Abiotic | | | |
| 5. Impact flow? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Primarily an agricultural weed, not known to grow in aquatic/riparian zones. Little or negligible impact to water flow. | L | M |
| 6. Impact water quality? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Primarily an agricultural weed, not known to grow in aquatic/riparian zones. No noticeable effects on dissolved O2 or light levels. | L | M |
| 7. Increase soil erosion? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Moderate probability of large scale soil movement. | ML | M |
| 8. Reduce biomass? | Insufficient information. | M | L |
| 9. Change fire regime? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Insufficient. | M | L |
| Community Habitat | | | |
| 10. Impact on composition (a) high value EVC | EVC = Plains Grassland(E); CMA = North Central; Bioregion = Victorian Riverina; VH CLIMATE potential. Sandy shores, disturbed ground, elevation 0-500 m (FNA undated). Sand. Road verges, wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Sandy shores, disturbed ground, perennial crops, grasslands (Fed Noxious Weeds undated). In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is less wide-spread [than emex australis] and, at this stage is most commonly found in parts of the Eyre Peninsula (Fromm 1996). Minor displacement of some dominant or indicator species within any one layer/strata. | ML | H |
| (b) medium value EVC | EVC = Riverine Chenopod Woodland (D); CMA = Wimmera; Bioregion = Murray Mallee; VH CLIMATE potential. Sandy shores, disturbed ground, elevation 0-500 m (FNA undated). Sand. Road verges, wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Sandy shores, disturbed ground, perennial crops, grasslands (Fed Noxious Weeds undated). In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is less wide-spread [than emex australis] and, at this stage is most commonly found in parts of the Eyre Peninsula (Fromm 1996). Very little displacement of any indigenous species, sparse and scattered infestations. | L | H |
| (c) low value EVC | EVC = Loamy Sands Mallee (LC); CMA = Mallee; Bioregion = Robinvale Plains; VH CLIMATE potential. Sandy shores, disturbed ground, elevation 0-500 m (FNA undated). Sand. Road verges, wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Sandy shores, disturbed ground, perennial crops, grasslands (Fed Noxious Weeds undated). In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is less wide-spread [than emex australis] and, at this stage is most commonly found in parts of the Eyre Peninsula (Fromm 1996). Minor displacement of some dominant or indicator species within any one layer/strata. | ML | H |
| 11. Impact on structure? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990). Minor or negligible impact on <20% of the floral strata/layers present | L | M |
| 12. Effect on threatened flora? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Impacts on threatened flora are undocumented. | MH | L |
| Fauna | | | |
| 13. Effect on threatened fauna? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990). Impacts on threatened fauna are undocumented. | MH | L |
| 14. Effect on non-threatened fauna? | Small burrs. Emex spinosa, grows in pasture and irritate livestock when they step on them. (Jackson 2004). Causes injury to livestock with spiny fruits (Scher undated). Minor effects on fauna species; minor hazard. | ML | M |
| 15. Benefits fauna? | Small burrs. Emex spinosa, grows in pasture and irritate livestock when they step on them. (Jackson 2004). Causes injury to livestock with spiny fruits (Scher undated). Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990). Emex spinosa is an erect, annual herb, up to 40 cm tall (Jackson 2004). Provides very little support to desirable species. | H | M |
| 16. Injurious to fauna? | E. spinosa is very similar to E. australis but with fruits and spines half the size (Declared Plants WA). Emex spinosa, grows in pasture and irritate livestock when they step on them. (Jackson 2004). Causes injury to livestock with spiny fruits (Scher undated). Spines, burrs or toxic properties to fauna at certain times of year. | MH | M |
| Pest Animal | | | |
| 17. Food source to pests? | Small burrs (Jackson 2004). Provides minimal food for pest animals. | L | M |
| 18. Provides harbour? | Emex spinosa is an erect, annual herb, up to 40 cm tall (FedNox Weeds undated) Doesn’t provide harbour for major pest species, but may provide for minor pest species. | ML | M |
| Agriculture | | | |
| 19. Impact yield? | In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is a more recent arrival to Australia has become naturalised, and it’s potential as a weed is yet to be discovered. (Scott et al. 1996). The South Australian NRM states E. spinosa is similar to E. australis except smaller. E. australis is a crop and pasture competitor which contaminates dry vine fruit, field peas and lucerne hay. It does not cause agricultural problems in the higher rainfall environment of the Mt Lofty Ranges and Lower South East (SA NRM undated). Minor impact on quantity of produce (<5% reduction). | ML | M |
| 20. Impact quality? | In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is a more recent arrival to Australia has become naturalised, and it’s potential as a weed is yet to be discovered. (Scott et al. 1996). The South Australian NRM states E. spinosa is similar to E. australis except smaller. E. australis is a crop and pasture competitor which contaminates dry vine fruit, field peas and lucerne hay. It does not cause agricultural problems in the higher rainfall environment of the Mt Lofty Ranges and Lower South East (SA NRM undated). Minor impact on quality of produce (<5% reduction). | ML | M |
| 21. Affect land value? | In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is a more recent arrival to Australia has become naturalised, and it’s potential as a weed is yet to be discovered. (Scott et al. 1996). The South Australian NRM states E. spinosa is similar to E. australis except smaller. E. australis is a crop and pasture competitor which contaminates dry vine fruit, field peas and lucerne hay. It does not cause agricultural problems in the higher rainfall environment of the Mt Lofty Ranges and Lower South East (SA NRM undated). Decreases land value <10% | M | M |
| 22. Change land use? | In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is a more recent arrival to Australia has become naturalised, and it’s potential as a weed is yet to be discovered. (Scott et al. 1996). The South Australian NRM states E. spinosa is similar to E. australis except smaller. E. australis is a crop and pasture competitor which contaminates dry vine fruit, field peas and lucerne hay. It does not cause agricultural problems in the higher rainfall environment of the Mt Lofty Ranges and Lower South East (SA NRM undated). Insufficient information/ | M | L |
| 23. Increase harvest costs? | In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Emex spinosa is a more recent arrival to Australia has become naturalised, and it’s potential as a weed is yet to be discovered. (Scott et al. 1996). Emex spinosa (L.) is a common weed in cereal crops and pastures in northern Tunisia. The build up of the seed bank from a cropping-grazing farming system makes chemical and cultural controls inefficient. (Kammoun 2009). Minor increase in cost of harvesting – e.g. slightly more time or labour is required. | M | MH |
| 24. Disease host/vector? | Unknown. | M | L |
Invasive
QUESTION | COMMENTS | RATING | CONFIDENCE |
| Establishment | | | |
| 1. Germination requirements? | In Emex spinosa, over 78% of subterranean achenes emerged from depths of 1-4 cm, but no germination occurred on the soil surface (Cheplick 1987). Subterranean achenes were less dormant, had a higher percentage of viability, germinated at a faster rate, were less temperature-dependent in germination and produced larger seedlings than aerial achenes. Subterranean achenes germinated equally well in light or dark, but aerial achenes had a strong light requirement (Weiss 1980). Requires natural seasonal disturbances such as seasonal rainfall, spring/summer temperatures for germination. | MH | M |
| 2. Establishment requirements? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990). Requires more specific requirements to establish (e.g. open space or bare ground with access to light and direct rainfall). | ML | MH |
| 3. How much disturbance is required? | Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990) Emex spinosa grows in pasture (Jackson 2004). Sandy shores, disturbed ground, perennial crops, grasslands (Scher undated). In Australia it is found growing ‘along roadsides and in vineyards, cereal crops and pastures’ (Weiss 1980). Establishes in overgrazed pastures/poorly growing or patchy crops. | ML | MH |
| Growth/Competitive | | | |
| 4. Life form? | Annual herb (Spooner 2007). Other. | L | M |
| 5. Allelopathic properties? | None mentioned in literature. Unknown. | L | M |
| 6. Tolerates herb pressure? | Small burrs (Spooner 2007). Emex australis is not readily eaten by stock, except at the seedling stage, Unknown. | M | L |
| 7. Normal growth rate? | Unknown. | M | L |
| 8. Stress tolerance to frost, drought, w/logg, sal. etc? | 0-500 m elevation (FNA undated). . Habitat: in sand; occupying road verges; growing on wasteland (Spooner 2007). Recorded once on disturbed pasture in Western Australia (Wilson 1990). Unknown. | M | L |
| Reproduction | | | |
| 9. Reproductive system | Reproducing by seed (Weiss 1980). No evidence of vegetative reproduction. Sexual (either cross or self pollination). | L | M |
| 10. Number of propagules produced? | Unknown. | M | L |
| 11. Propagule longevity? | Seeds from both Emex species can remain dormant in the soil for more than seven years (CSIRO 2007). Greater than 25% of seeds survive in the soil. | ML | MH |
| 12. Reproductive period? | Annual (Spooner 2007). Mature plants produce viable propagules for only one year. | L | M |
| 13. Time to reproductive maturity? | Annual (Spooner 2007). Reaches maturity and produces viable propagules in under a year. | H | M |
| Dispersal | | | |
| 14. Number of mechanisms? | E. spinosa is very similar to E. australis but with fruits and spines half the size (Declared Plants WA). Presumably seeds of Emex spinosa float the same as Emex asutralis (SA NRM). ‘two main steps of Emex contaminating dried fruit are by attachment to plastic picking baskets and falling into produce, and also attachment to shoes and clothes of workers and parts of the drying mechanisms’ (Pohlner 1996). Propagules spread by water and attachment. | MH | ML |
| 15. How far do they disperse? | E. spinosa is very similar to E. australis but with fruits and spines half the size (Declared Plants WA). Presumably seeds of Emex spinosa float the same as Emex asutralis (SA NRM). ‘two main steps of Emex contaminating dried fruit are by attachment to plastic picking baskets and falling into produce, and also attachment to shoes and clothes of workers and parts of the drying machinery’ (Pohlner 1996). Few propagules will disperse greater than one kilometre, many will reach 200-1000 m | MH | ML |
References
Cheplick GP (1987) Ecology of Amphicarpic Plants. Trends In Ecology and Evolution 2: 97-101.
FNA (undated) Flora of North America. Available at www.efloras.org
Jackson K (2004) Red Apion Weevil released as control for three-corner-jacks. South Australia Country Hour Feature Story
SA NRM (undated) Declared Plant Policy three corner jack (Emex species). PDF available online at
http://www.dwlbc.sa.gov.au/assets/files/NRMPolicies_threecorner_jack_policy.pdf (verified 17 November 2009).
Spooner A (2007) PlantNet, Flora of Western Australia. Available at http://florabase.dec.wa.gov.au/
Weiss PW (1980) Germination, reproduction and interference in the amphicarpic annual Emex spinosa (L.) Campd. Oecologica 44 244-251.
Wilson KL (2007) Biological Control of Weeds Annual Review of Entomology 9 pp 225-244.
Global present distribution data references
Australian National Herbarium (ANH) (2009) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at http://www.anbg.gov.au/avh/ (verified 17 November 2009).
Department of the Environment and Heritage (Commonwealth of Australia). (1993 – On-going) Australian Plant Name Index (APNI) http://www.cpbr.gov.au/apni/index.html (verified 17 November 2009).
Calflora: Information on California plants for education, research and conservation. [web application]. (200X) Berkeley, California: The Calflora Database [a non-profit organization]. Available at http://www.calflora.org/ (verified 17 November 2009).
Global Biodiversity Information Facility (GBIF) (2009) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 17 November 2009).
Integrated Taxonomic Information System. (2009) Available at http://www.itis.gov/ (verified 17 November 2009).
Missouri Botanical Gardens (MBG) (2009) w3TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html (verified 17 November 2009).
National Biodiversity Network (2004) NBN Gateway, National Biodiversity Network, UK, Available at http://www.searchnbn.net/index_homepage/index.jsp (verified 17 November 2009).
Royal Botanic Gardens Melbourne. (2002) Census of Vascular Plants of Victoria. Available at http://www.rbg.vic.gov.au/research_and_conservation/plant_information/viclist (verified 17 November 2009).
United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2009) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 17 November 2009).
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