Cynoglossum creticum Mill.

Title: Cynoglossum creticum Mill.

Scientific Name:

Cynoglossum creticum Mill.

Common Names:

blue hound’s tongue

Image via GBIF

Habitat:

Found in warm temperate grassland communities which occur at altitudes of 0 – 1,000 m. Most commonly occurs on disturbed sites such as roadsides, sand dunes or open woodlands. Tolerant of dry conditions. (CRC for Australian Weed Management 2003)

Distribution:

Map via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Germinates in autumn and flowers in spring-summer (CRC for Australian Weed Management 2003). Requires natural seasonal conditions.

2. Establishment requirements? No information available regarding C. creticum although C. officinale (the most closely related species which is also biennial herb found in same habitats) is shade tolerant and can occur in areas of thick litter accumulation (USFS 2003). As C. creticum can also occur in open woodlands, assume it too can establish under a moderate canopy.

3. How much disturbance is required? Invades grasslands. Most commonly grows on disturbed sites such as roadsides, sand dunes or open woodlands, where it establishes and spreads quickly’ (CRC for Australian Weed Management 2003). Although prefers disturbed sites, can establish in minor disturbed natural ecosystem.

GROWTH / COMPETITIVE

4. Life form? A biennial herb (USFS 2003) – life form – other.

5. Allelopathic properties? None described in USFS 2003.

6. Tolerates herb pressure? ‘leaves contain pyrrolizidine alkaloids that kill cattle and horses. ‘.. insects tend to avoid the plant because of the alkaloids in its leaves’ (CRC for Australian Weed Management 2003). Favoured by heavy grazing as not eaten by animals.

7. Normal growth rate? ‘Invades grasslands and suppresses native grasses’. ‘Seedlings are fast growing’ (CRC for Australian Weed Management 2003). Assume that plant will equal competitive species of same life form.

8. Stress tolerance to frost, drought, w/logg, sal. etc? ‘Fire probably top-kills hounds tongue plants’ (CRC for Australian Weed Management 2003). C. officinale, a closely related species, does not tolerate waterlogging and is frost susceptible (USFS 2003). Insufficient information available on C. creticum. Score as medium.

REPRODUCTION

9. Reproductive system? ‘Spreads by seeds’ (CRC for Australian Weed Management 2003). Does not vegetatively reproduce. No evidence in literature to suggest if self or cross-pollinates.

10. Number of propagules produced?‘ .. mature plants each producing several hundred [seeds]’ (CRC for Australian Weed Management 2003). Likely that plant produces between 50 to 1,000 propagules per flowering event.

11. Propagule longevity? ‘Plant dies after flowering, but seeds may stay attached until the following spring, delaying germination for a year’ (CRC for Australian Weed Management 2003). Viability is two to three years.

12. Reproductive period? ‘Lifecycle that is completed in two years or seasons, with the second season usually devoted to flowering and fruiting’ (CRC for Australian Weed Management 2003).

13. Time to reproductive maturity? ‘Lifecycle that is completed in two years or seasons, with the second season usually devoted to flowering and fruiting’ (CRC for Australian Weed Management 2003).

DISPERSAL

14. Number of mechanisms? ‘In North America cattle and wildlife are important dispersers of the closely related C. officinale .. likely also to be the case in Australia’ (CRC for Australian Weed Management 2003). ‘Seeds may be transported by animals or people into disturbed areas where they find suitable conditions for germination.’

15. How far do they disperse? ‘Spread long distances attached to people or animals’ (CRC for Australian Weed Management 2003). Very likely that some propagules will disperse greater than 1 km.

Impact Assessment

RECREATION

1. Restrict human access? ‘Although flowers have hooks, the plants only grow up to 600 mm high’ (CRC for Australian Weed Management 2003). Weed would have a minimal or negligible impact on human access.

2. Reduce tourism? Grows up to 600 mm high and typically occurs on roadsides, pastures, grasslands. Plant also has hooks (CRC for Australian Weed Management 2003). Visitor may be aware of weed but not bothered or activity not inhibited.

3. Injurious to people? ‘Flowers are covered in hooks’ (CRC for Australian Weed Management 2003). These hooks can attach to people at certain times of year.

4. Damage to cultural sites? Not likely to cause damage to cultural sites.

ABIOTIC

5. Impact flow? Terrestrial species.

6. Impact water quality? Terrestrial species.

7. Increase soil erosion? Plant has long taproot. Although the plant dies off after flowering and may leave some of the ground exposed, (CRC for Australian Weed Management 2003) low probability of large scale soil movement.

8. Reduce biomass? ‘It invades grasslands and suppresses native grasses’ (CRC for Australian Weed Management 2003). Grows up to 600 mm high so likely that biomass will increase.

9. Change fire regime? Plants die off after flowering. Invades grasslands and suppresses native grasses. Weed may have small or negligible effect on fire risk.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC= Damp sands herb rich woodland (V); CMA=East Gippsland; Bioreg=East Gippsland Lowland; CLIMATE potential=VH. ‘Invades grasslands and suppresses native grasses’ (CRC for Australian Weed Management 2003). Minor displacement of some dominant species within the groundcover layer.

10(b) Impact on medium value EVC? VC= Valley grassy forest (D); CMA=East Gippsland; Bioreg=East Gippsland Upland; CLIMATE potential=VH. ‘Invades grasslands and suppresses native grasses’ (CRC for Australian Weed Management 2003). Major displacement of some dominant species within the groundcover layer.

10(c) Impact on low value EVC? EVC= Coastal Banksia Woodland (LC); CMA=East Gippsland; Bioreg=East Gippsland Lowland; CLIMATE potential=VH. ‘Invades grasslands and suppresses native grasses’ (CRC for Australian Weed Management 2003). Minor displacement of some dominant species within the groundcover layer.

11. Impact on structure? ‘Invades grasslands and suppresses native grasses’ (CRC for Australian Weed Management 2003). When occurring in open areas where only one stratum present likely to have a minor effect on greater than 60% of the layers (MH). In open woodlands, likely to have a minor effect on 20-60% of the floral strata (ML). Therefore score as medium.

12. Effect on threatened flora? This species is not documented as posing an additional risk to threatened flora.

FAUNA

13. Effect on threatened fauna? This species is not documented as posing an additional risk to threatened fauna.

14. Effect on non-threatened fauna? Weed is mostly a pasture weed so greatest impact on domesticated animals (CRC for Australian Weed Management 2003). ‘Horses may be especially affected when restricted to small, infested area without other desirable forage’ (Graham & Johnson 2003). Weed may have a minor effect on fauna spp.

15. Benefits fauna? Weed not documented to provide benefit to indigenous fauna.

16. Injurious to fauna? Leaves are toxic to livestock. ‘Plant has burrs that attach to cattle, causing irritation’. ‘Leaves contain pyrrolizidine alkaloids that kill cattle and horses’ (CRC for Australian Weed Management 2003).

PEST ANIMAL

17. Food source to pests? Not known to be a food source to pests.

18. Provides harbor? Not known to provide harbour for pest spp.

AGRICULTURE

19. Impact yield? ‘Grazing and dairy farms throughout [humid temperate and subhumid zones of Australia] would potentially be affected by a loss of pasture and stock’ (CRC for Australian Weed Management 2003). Potential to have a major impact on quantity of produce (5-20%).

20. Impact quality? C. officinale (a closely related species) also has prickly seeds which ‘are very hard to remove after they cling to animals, thus lowering the wool value of sheep’. If the leaves of C. creticum are contained in hay or chopped forage, then possible that the cattle and horses will die if they eat it. Leaves have a serious toxicity effect (CRC for Australian Weed Management 2003). Likely to have a major impact on quality of produce.

21. Affect land values? No evidence to suggest the weed will affect land value.

22. Change land use? Not known to cause a change in priority of land use.

23. Increase harvest costs? No evidence to suggest the weed will increase the cost of harvest.

24. Disease host/vector? Not a known host or vector for disease.

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 Nature's Weeding Centre.

Attachments:

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referenced by (1)

wra825: Common Name - B (via blue hounds tongue)

Article: wra8496 (permalink)
Categories: :wra:c, :wra:inv1, :wra:invmh, :wra:inv2, :wra:invm, :wra:inv3, :wra:inv4, :wra:invl, :wra:inv5, :wra:inv6, :wra:invh, :wra:inv7, :wra:inv8, :wra:inv9, :wra:inv10, :wra:invml, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impl, :wra:imp2, :wra:impm, :wra:imp3, :wra:impml, :wra:imp4, :wra:imp5, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:impmh, :wra:imp10c, :wra:imp11, :wra:imp12, :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: 17 February 2023; 6:31:43 PM AEDT

Author Name: David Low
Author ID: adminDavid