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Species
Tussilago farfara L.
IUCN
NCBI
EOL Text
Canada
Origin: Exotic
Regularity: Regularly occurring
Currently: Unknown/Undetermined
Confidence: Confident
United States
Origin: Exotic
Regularity: Regularly occurring
Currently: Unknown/Undetermined
Confidence: Confident
License | http://creativecommons.org/licenses/by-nc/3.0/ |
Rights holder/Author | NatureServe |
Source | http://explorer.natureserve.org/servlet/NatureServe?searchName=Tussilago+farfara |
More info for the terms: fresh, natural
Coltsfoot seeds do not show dormancy. Secondary dormancy does not occur in coltsfoot. Seeds usually germinate the season they are produced [10]. Under laboratory and natural conditions, seed viability decreases rapidly over time. Most seeds >5 months old do not germinate [4,10,64]. Under laboratory conditions in the Netherlands, mean percent germination of coltsfoot seeds decreased from 94% immediately after harvest to 3% 4 months later [4]:
Mean percent germination of coltsfoot seeds immediately after harvest and after storage under varied conditions [4] | ||||
Storage conditions | Storage time | |||
Immediately after harvest | 1 month | 2 months | 4 months | |
Indoors, 18-23 °C | 94 | 57 | 41 | 3 |
Outdoors, 40 cm below the soil surface | 94 | 21 | 3 | 0 |
Outdoors, 50 cm below the water surface | 94 | 37 | 0 | 0 |
Coltsfoot seeds collected in May from wild populations in Poland and sown on filter paper in May and June reached 100% germination within 24 hours. Seeds sown in July reached 92% germination within 3 days; those sown in September reached 4.7% germination in 6 days; none of those sown in October germinated [64]. All coltsfoot seeds collected in April and May from wild populations in England and planted immediately after harvesting germinated in the laboratory. All seeds stored for 8 weeks at 37 °F (3 °C) also germinated in the laboratory, suggesting no loss of viability during 8 weeks of storage. However, all seeds stored at 37 °F for 6 months, then stored for an additional 6 months either at 81 °F (27 °C) in the laboratory or buried in mesh bags in potting soil outside, failed to germinate [10].
Viability and germination of coltsfoot seeds in the laboratory are high [4,10,64] but may not reflect germination rates in wild populations [64]. In laboratory experiments, viability reported for coltsfoot seeds from wild populations ranged from about 52% [11] to 76% [10]. However, seed germination in the field may be much lower than that in the laboratory. Namura-Ochalska [64] reported that even in years of high seed production, "no more than a few seedlings emerged", with as few as 0.5% of seeds germinating.
Coltsfoot seeds germinate in a range of light, temperature, soil moisture, and soil pH conditions, but cold temperatures and dry or extremely acid soils inhibit germination. Coltsfoot seeds germinate equally well in light and in dark [4,10,64]. Fresh coltsfoot seeds germinate at constant temperatures ranging from 41 to 86 °F (5-30 °C) [10], but >50 to 77 °F (10-25 °C) is optimum [4,6,10]. Coltsfoot seeds germinate well on substrates with a range of water availability, although they germinate best on moist substrates [10,64]. In the laboratory in Poland, seedling emergence tests indicated that coltsfoot seeds tolerated excess water, including submergence, but were very susceptible to water shortage [64]. In a culture solution, coltsfoot seeds germinated at a pH ranging from 4.5 to 6.5; germination was "slow" at pH 4; and no seeds germinated at pH <3.5 [62].
Seedling emergence tests indicate that coltsfoot seeds germinate best when on the soil surface, and seeds buried deeper than 0.2 inch (0.5 cm) [4] to 0.8 inch (2 cm) [64] do not germinate. In the laboratory in Poland, 100% of seeds planted on the soil surface germinated within 2 days; 50% germinated within 9 days when planted 0.4 inch (1 cm) deep; and 12% germinated within 12 days when planted 0.8 inch (2 cm) deep. Seeds sown deeper did not germinate [64].
This plant is not threatened.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | Copyright Wildscreen 2003-2008 |
Source | http://www.arkive.org/colts-foot/tussilago-farfara/ |
Coltsfoot is nonnative in North America. It is most widespread in the eastern United States from Minnesota south to Tennessee, east to North Carolina, and north to Maine [36,43,57,95,106]. It occurs throughout southern Ontario, southern Quebec, and the Canadian Maritime provinces. It is also found in southwestern British Columbia and Vancouver Island [83] and occasionally west of the Cascade Range in the Pacific Northwest [43]. Plants Database provides a distributional map of coltsfoot.
Coltsfoot is native to Europe, western Asia, and northwestern Africa ([33,36,43], Hulten and Fries 1986 cited in [48]). Coltsfoot's native geographical distribution extends from the British Isles east to Siberia, north to the Arctic Circle, and south to the Himalayas [62]. Coltsfoot was probably introduced from its native range to the United States by early European settlers for its medicinal properties (see Other Uses) [95]. It was present in the United States as early as 1840 [105] and present in Canada in the 1920s [109]. Coltsfoot has escaped from cultivation and has spread extensively (see Impacts) [48].
More info for the terms: density, succession
Coltsfoot is sexually mature in its second year (see Seasonal Development) [7]. A fact sheet states that each coltsfoot plant produces about 3,500 seeds [109]. In Manchester, England, coltsfoot plants grown in pots outside produced 4,600 seeds/plant on average [11]. According to a flora, a single flower head may produce 100 to 1,000 seeds, although typically no more than 300 [33]. In England, one wild population of coltsfoot produced an average of 157 seeds/flower head [13], and another produced 178 seeds/flower head [11]:
Reproductive characteristics of a wild coltsfoot population in Manchester, England [11] | |
Seeds/flower head | 178.1 |
Loss of seeds to predation (%) | 21.0 |
Flower heads/rootstock | 7.7 |
Flower heads/rootstock of the largest plant | 100 |
Seeds/rootstock, including loss of seeds to predation | 1,080 |
Coltsfoot seed production may be variable among populations and years. In its native range in Poland, a coltsfoot population along a riverbank produced 23,308 seeds/m² one year and <500 seeds/m² the previous year. The author attributed the difference in part to weather. In the same study, coltsfoot seed production decreased 51-fold in an old field and 22-fold in a grassland over 4 years. The author attributed the decline to succession of sod-forming grasses [64]. In the Netherlands, coltsfoot planted on bare, unvegetated soil produced 226,715 seeds/m², whereas coltsfoot planted in a young forest produced 16,511 seeds/m² [4]:
Reproductive characteristics of coltsfoot planted in 2 habitats in the Netherlands [4] | ||
Variable | Unshaded site* | Shaded site** |
Flowering stems/m² | 33 | 7 |
Flower heads/flowering stem | 37 | 16 |
Seeds/flower head | 211 | 162 |
Mean percent seed germination | 88 | 91 |
Number of viable seeds/m² | 226,715 | 16,511 |
*A bare, unvegetated site. Soils were moderately moist clay loam, aerated to a depth of 30-40 cm. ** A young forest (3-4 m tall), without groundlayer vegetation. Light intensity in July was 35-45% of full daylight. Soils were moderately moist clay loam, aerated to a depth of 50 cm. |
In its native range in Denmark, coltsfoot did not produce seeds every year [1]. Coltsfoot seed production may be influenced by plant density. For more information on this topic, see Vegetative regeneration.
More info for the terms: cover, density, fire management, invasive species, natural, prescribed fire, rhizome
Impacts: Coltsfoot often forms dense stands, particularly along roadsides (e.g., [21,22,59]), and occasionally dominates disturbed native plant communities (e.g., [2,80]). Coltsfoot's ability to dominate disturbed areas is attributed to its high seed production, fast vegetative spread, and ability to tolerate a wide range of environmental conditions [66,77]. According to management guidelines from 2005, however, evidence was lacking that coltsfoot out-competes other vegetation in relatively undisturbed native habitats [58]. In 2004, a compilation of invasive species lists and expert opinion from throughout the northeastern and north-central United States indicated that coltsfoot was “not currently known to be especially invasive” [101]. Although coltsfoot was introduced in Canada in the 1920s, Wright [109] stated that by 1997 it had not spread extensively. Most fact sheets, government publications, and weed management guides indicated that coltsfoot had no more than a moderate impact on native vegetation [20,26,95,101]. In the Upper Midwest, coltsfoot appears most invasive in grasslands and wetlands [26]. In Massachusetts, coltsfoot appears most invasive in lime seeps and disturbed sites [58].
Photo courtesy of Leslie J. Mehrhoff, University of Connecticut, Bugwood.org |
Control: Coltsfoot control is complicated by its abundant seed production and ability to sprout from rhizomes following disturbance [77,109]. Because coltsfoot often becomes established after disturbance, control efforts should focus on management of existing infestations and minimization of disturbance to forests, wetlands, and other natural communities. Control effectiveness may depend on a program that integrates multiple management procedures such as herbicides, seeding of desired species, and other techniques that decrease coltsfoot spread and favor desired species.
In all cases where invasive species are targeted for control, no matter what method is employed, the potential for other invasive species to fill their void must be considered [17]. Control of biotic invasions is most effective when it employs a long-term, ecosystem-wide strategy rather than a tactical approach focused on battling individual invaders [55].
Prevention: Coltsfoot's preference for disturbed sites (see Successional Status) suggests that its establishment may be prevented by minimizing soil disturbance. It is commonly argued that the most cost-efficient and effective method of managing invasive species is to prevent their establishment and spread by maintaining "healthy" natural communities [55,87] (e.g., avoid road building in wildlands [100]) and by monitoring several times each year [49]. Managing to maintain the integrity of the native plant community and mitigate the factors enhancing ecosystem invasibility is likely to be more effective than managing solely to control the invader [44].
Weed prevention and control can be incorporated into many types of management plans, including those for logging and site preparation, grazing allotments, recreation management, research projects, road building and maintenance, and fire management [102]. See the Guide to noxious weed prevention practices [102] for specific guidelines in preventing the spread of weed seeds and propagules under different management conditions.
Fire: For information on the use of prescribed fire to control this species, see Fire Management Considerations.
Cultural control: Because increased vegetation density and cover may result in decreased coltsfoot cover (see Successional Status), it may be possible to control coltsfoot by establishing native vegetation. In a greenhouse in Poland, coltsfoot seedling survival decreased with increased seedling density, and increased seedling density also delayed coltsfoot seedling development [66]. In field experiments in the Netherlands, coltsfoot did not grow well from germination to the reproductive stage when grown among dense agricultural crops, due in part to low light intensities under these crops [4]. Other researchers reported that because coltsfoot was low-growing, vegetative reproduction was reduced by the abundance of other low-growing herbs such as clover (Fabaceae) and ryegrass (Lolium spp.) (review by [4]). In combination, these studies suggest that establishing native vegetation may slow coltsfoot establishment and spread. For more information on this topic, see Seedling establishment and plant growth.
Physical or mechanical control: Coltsfoot has deep, brittle rhizomes, making it difficult to control by hand-pulling. Small coltsfoot infestations may be eradicated by carefully digging out plants [26,95]. It is critical that all underground portions of the plant are removed because even small fragments of rhizomes left in the soil are likely to give rise to new plants [66]. According to a fact sheet, coltsfoot roots can remain dormant underground for long periods [95] and presumably retain the potential to generate new plants. Coltsfoot seedlings hand-pulled after germination but prior to rhizome development are usually killed and not capable of vegetative reproduction (see Vegetative regeneration) [4]. Hand-pulling before the plant has set seed may reduce spread [95].
Biological control: No biological controls of coltsfoot are known as of this writing (2011). Biological control of invasive species has a long history that indicates many factors must be considered before using biological controls. Refer to these sources: [104,108] and the Weed control methods handbook [98] for background information and important considerations for developing and implementing biological control programs.
Chemical control: Herbicides may control coltsfoot. Fact sheets provide information on specific chemicals that may be used to control coltsfoot: [95,109]. However, little detailed information regarding the effectiveness of herbicides on coltsfoot was available as of this writing (2011). Herbicides are effective in gaining initial control of a new invasion or a severe infestation, but they are rarely a complete or long-term solution to weed management [18]. See the Weed control methods handbook [98] for considerations on the use of herbicides in natural areas and detailed information on specific chemicals.
Integrated management: Integrated management includes considerations of not only killing the target plant but also of establishing desirable species and maintaining weed-free systems over the long term. Integrated management techniques may be more effective than individual methods at controlling coltsfoot, but as of this writing (2011) no information was available.
Common throughout Britain, reaching heights of up to 1065m in Scotland (2) (3). Elsewhere, this species is found throughout most of Europe reaching its northernmost extreme in Norway. It also occurs in North Africa, western and northern Asia, and has been introduced to North America (2).
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | Copyright Wildscreen 2003-2008 |
Source | http://www.arkive.org/colts-foot/tussilago-farfara/ |
Pollination and breeding system: Coltsfoot may self-pollinate, but it is principally cross-pollinated [4,34,62] by insects [11,33,62]. Self-pollination "does not...appear to be very successful as may be seen from the numerous shriveled empty fruits...found in most heads if insects are excluded" [62]. In its native range, coltsfoot is pollinated by bees (Hymenoptera) [71,73], hoverflies (Syrphidae), flies (Diptera), beetles (Coleoptera), and possibly ants (Formicidae) [73].
Conservation action is not required for this species at present.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | Copyright Wildscreen 2003-2008 |
Source | http://www.arkive.org/colts-foot/tussilago-farfara/ |
N. Africa, Europe, Asia eastwards to China, introduced in N. America.
License | http://creativecommons.org/licenses/by-nc-sa/3.0/ |
Rights holder/Author | eFloras.org Copyright © Missouri Botanical Garden |
Source | http://www.efloras.org/florataxon.aspx?flora_id=110&taxon_id=200024610 |