Digitalis purpurea L. (digitalis, foxglove), SYNONYMS: ( Digitalis amandiana Samp., Digitalis miniana Samp., Digitalis nevadensis Kunze, Digitalis tomentosa Hoffmans. & Link) Scrophulariaceae (Plantaginaceae)

Answer

Score

1.01

Is the species highly domesticated?

y=-3, n=0

n

0

1.02

Has the species become naturalized where grown?

y=1, n=-1

1.03

Does the species have weedy races?

y=-1, n=-1

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

0

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

2

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

1

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

1

2.05

Does the species have a history of repeated introductions outside its natural range?

y=-2, ?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

y

0.5

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

y

0.5

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

n

0

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

y

0.5

4.01

Produces spines, thorns or burrs

y=1, n=0

n

0

4.02

Allelopathic

y=1, n=0

n

0

4.03

Parasitic

y=1, n=0

n

0

4.04

Unpalatable to grazing animals

y=1, n=-1

n

-1

4.05

Toxic to animals

y=1, n=0

y

1

4.06

Host for recognized pests and pathogens

y=1, n=0

n

0

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

y

1

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

0

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

n

0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

1

4.11

Climbing or smothering growth habit

y=1, n=0

n

0

4.12

Forms dense thickets

y=1, n=0

y

1

5.01

Aquatic

y=5, n=0

n

0

5.02

Grass

y=1, n=0

n

0

5.03

Nitrogen fixing woody plant

y=1, n=0

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

0

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

0

6.02

Produces viable seed.

y=1, n=-1

y

1

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

y

1

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

n

-1

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

2

0

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

-1

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

1

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

-1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

1

7.05

Propagules water dispersed

y=1, n=-1

y

1

7.06

Propagules bird dispersed

y=1, n=-1

n

-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

-1

7.08

Propagules survive passage through the gut

y=1, n=-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

y

1

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

y

1

8.03

Well controlled by herbicides

y=-1, n=1

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

n

-1

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

7.5

Notes

Source

1.01

(1) The Foxglove is cultivated by a few growers in this country in order to provide a drug of uniform activity from a true type of Digitalis purpurea. It is absolutely necessary to have the true medicinal seeds to supply the drug market: crops must be obtained from carefully selected wild seed and all variations from the new type struck out.

(1) Grieve, Margaret. 1931. A Modern Herbal. Harcourt, Brace & Company

1.02

1.03

2.01

(1) Native to Northern Africa: Morocco, Northern Europe: Denmark; Finland; Ireland; Norway; Sweden; United Kingdom Middle Europe:Belgium;Czechoslovakia;Germany,Southeastern Europe: Italy - Sardinia Southwestern Europe: France [incl. Corsica]; Portugal; Spain

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?13986

2.02

(1) Native to Northern Africa: Morocco, Northern Europe: Denmark; Finland; Ireland; Norway; Sweden; United Kingdom Middle Europe:Belgium;Czechoslovakia;Germany,Southeastern Europe: Italy - Sardinia Southwestern Europe: France [incl. Corsica]; Portugal; Spain

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?13986

2.03

(1) Able to grow in USDA hardiness zones 3-9

(1) http://www.wildflowerinformation.org/ZoneListing.asp

2.04

(1) Literature based distribution maps include Central America, Columbia, Ecuador, and Peru (2) Naturalized in Central America

(1) http://mobot.mobot.org/cgi-bin/search_vast (2) http://books.google.com/books?id=htGD3Y7WNxwC&pg=PA197&lpg=PA197&
dq=digitalis+purpurea+%22naturalized%22&source=web&ots=ViM0yd07IU&sig=-jYL8h5cvjZElNgvhAJoBOIfsgc&hl=en&sa=X&oi=book_result&resnum=6&ct=result#PPA197,M1

2.05

(1) Digitalis purpurea has been introduced from Europe and naturalized in various parts of North America.

(1) http://aggie-horticulture.tamu.edu/wildseed/27/27.4.html (2)

3.01

(1) Foxglove (Digitalis purpurea) is an attractive biennial plant that is cultivated in Canada and is naturalized in several provinces.(2) Native to Europe but sometimes naturalized in disturbed areas; low elevations. Jiangsu, Jiangxi, Sichuan, Zhejiang [Europe]. (3) Native to Europe, this plant is widly cultivated. It is a common garden escape and is naturalized in the U.S. Pacific Northwest. 

3.02

(1)Roots of young plants are not able to penetrate turf or litter. Soil disturbance greatly increases establishment of seedlings

(1)Harris, S.A. 2000. Digitalis purpurea L. In: Invasive plants of California’s wildlands. Edited by Bossard, C.C., J.M. Randall, and M.C. Hoshovsky. University of California Press. p. 158-161.

3.03

no evidence

3.04

3.05

(1) Digitalis lantana is considered a secondary noxious weed that can be added to a county's prohibited or restricted list under the Minnesota Noxious Weed Law (2) Digitalis lanata is weed in Minnesota

(1)http://www.mda.state.mn.us/news/publications/pestsplants/badplants/noxiousplantsminnesota.pdf (2) http://www.dot.state.mn.us/environment/pdf_files/grecian_foxglove.pdf

4.01

(1) No spines, thorns, or burrs

(1) http://zipcodezoo.com/Plants/D/Digitalis_purpurea/

4.02

(1) Purple foxglove is not known to be allelopathic

(1) USDA (United States Department of Agriculture), NRCS (Natural Resource Conservation Service). 2002. The PLANTS Database, Version 3.5 (http://plants.usda.gov).

4.03

(1) Fire associated with other management programs is problematic, since stands of foxglove are not a good fuel source. Also, habitat in which foxglove typically becomes established does not contain enough fuel to sustain a fire long enough to kill the plant.

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

4.04

(1) The book Veterinary Toxicology uses D. purpurea as an example of a palatable plant for grazing animals that is however toxic.

(1) http://books.google.com/books?id=NgMX__L3q40C&pg=PA195&lpg=PA195&dq=digitalis+purpurea+%22palatable%22&
source=web&ots=wqtu5r0r7b&sig=ws1FOktlVShn6W0VmvAtUoJLx78&hl=en&sa=X&oi=book_result&resnum=5&ct=result#PPA196,M1

4.05

(1) Poisonous to mammals (2) Upon ingestion, this plant can cause toxic reactions that lead to severe sickness and death in animals

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?13986 (2) http://www.cbif.gc.ca/pls/pp/ppack.info?p_psn=57&p_type=all&p_sci=sci&p_x=px

4.06

no evidence (1) Ramularia variabilis is a pathogen on D. purpurea but is not considered an important pathogen in the region.

(1) http://www.hear.org/pph/pathogens/3662.htm

4.07

(1) D. purpurea ingestion was fatal in a 64-year-old despite administration of Digibind. (2) Ingestion of D. purpurea was toxic in a patient. Leaves were mistaken for Borage. (3) Accidental poisoning of patient in Spain (4) Highly toxic, may be fatal.

(1) http://www.ncbi.nlm.nih.gov/pubmed/17968204?ordinalpos=2&itool=
EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum (2) http://www.ncbi.nlm.nih.gov/pubmed/11989129?ordinalpos=24&itool=
EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum (3) http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~g8UQiP:67 (4) http://www.ces.ncsu.edu/depts/hort/consumer/poison/Digitpu.htm

4.08

(1) Stands of foxglove are not a good fuel source. Also, habitat in which foxglove typically becomes established does not contain enough fuel to sustain a fire long enough to kill the plant.

(1)http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

4.09

(1) Foxglove does best in partial shade.

(1) http://www.floridata.com/ref/d/digi_pur.cfm

4.10

(1) pH 5.5-7.0 (2) prefers rich acidic soils but is adaptable (3) Tolerant of a wide range of soils, except very wet or very dry.

(1) http://www.thegrowspot.com/know/f7/all-about-purple-foxglove-digitalis-purpurea-16347.html (2) http://www.wildflowerinformation.org/Wildflower.asp?ID=45 (3) http://www.plantadvice.co.uk/plants/show_plant.php?id=113

4.11

(1) Herbs, one to few stems, caespitose

http://www.hear.org/pph/pathogens/3662.htm

4.12

(1) D. purpurea readily colonizes disturbed areas, forming dense patches that displace natural vegetation.

(1) http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_DIPU.pdf

5.01

Not aquatic

5.02

Not a grass

5.03

(1) Scrophulariaceae (Plantaginaceae) family does not fix nitrogen

(1) http://www.nationmaster.com/encyclopedia/nitrogen-fixation

5.04

(1) No underground storage organs

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

6.01

(1) In Western and Central Europe populations of D. purpurea become established in forest clearings at the onset of secondary succession. Non-reproducing individuals and vegetative and generative reproduction maintain the populations.

(1) van Baalen, J. 1982. Germination ecology and seed population dynamics of Digitalis purpurea. Oecologia (Berl) 53:61-67 (2) http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_DIPU.pdf

6.02

(1) J. van Baalen used seeds from a natural population of Digitalis to experiment on the germination ecology and seed population dynamics. (2) Foxglove reproduces only by seed. Seeds remain viable in the soil at least five years.

(1) van Baalen, J. 1982. Germination ecology and seed population dynamics of Digitalis purpurea. Oecologia (Berl) 53:61-67 (2) http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_DIPU.pdf

6.03

Unknown whether natural hybridization can occur (1)Abstract RAPD markers were used to study inter-specific variation among six species of the genus Digitalis: D. obscura, D. lanata, D. grandiflora, D. purpurea, D. thapsi and D. dubia, and the hybrid D. excelsior (D. purpurea ´ D. grandiflora). (2)A considerable number of plant breeders have obtained hybrids between Digitalis purpurea and D. lutea...

(1)Nebauer, S.G., L. del Castillo-Agudo and J. Segura. 2000. An assessment of genetic relationships within the genus Digitalis based on PCR-generated RAPD markers. Theor Appl Genet 100:1209–1216. (2)Warren, E. 1924. On an Interspecific Hybrid of Digitalis. Biometrika 16(3/4): 205-238.

6.04

(1) Here, I present the results from a study of the consequences of crossing distance on lifetime progeny fitness in a population of the autotetraploid, self-compatible, Digitalis purpurea L. (Plantaginaceae). (2)The flowers are self-compatible...In the absence of pollinators, D. purpurea is able to produce seeds by delayed selfing, although fruit and seed sets are variable.

(1)Grindeland, J.M. 2008. Inbreeding depression and outbreeding depression in Digitalis purpurea: optimal outcrossing distance in a tetraploid. Journal of Evolutionary Biology 21(3): 716–726. (2)Darwin, C. 1876. The Effects of Cross and Self Fertilisation in the Vegetable Kingdom. J. Murray, London.

6.05

(1) Bombus hortorum and B. terrestris were quantified as visiting Digitalis.

(1) Wassink E.C.1975. Mededelingen Landbouwhogeschool Wageningen. 75 (20):1-6

6.06

(1) Foxglove reproduces only by seed. Seeds remain viable in the soil at least five years

(1) http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_DIPU.pdf

6.07

(1) Biennial or perennial herb, produces flowering stalk in the 2nd year

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

7.01

no evidence

7.02

(1) Digitalis has been introduced to many areas as an ornamental and medicinal plant

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

7.03

No evidence

7.04

(1) The small andnumerous seeds are dispersed by wind and water (2) It escapes cultivation, and seeds are dispersed by wind and water.

(1) http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_DIPU.pdf (2) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

7.05

(1) The small andnumerous seeds are dispersed by wind and water (2) It escapes cultivation, and seeds are dispersed by wind and water.

(1) http://akweeds.uaa.alaska.edu/pdfs/species_bios_pdfs/Species_bios_DIPU.pdf (2) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

7.06

(1) Digitalis purpurea spreads its seeds ballistically. (2) Capsules

(1) Sletvold, N. 2005. Density-dependent growth and survival in a natural population of the facultative biennial Digitalis purpurea. Journal of Ecology 93:727-736.(2) http://zipcodezoo.com/Plants/D/Digitalis_purpurea/

7.07

(1)The small and numerous seeds are dispersed by wind and water. However, the seeds lack specific adaptations for wind or animal dispersal. [No means of external attachment]

(1)Harris, S.A. 2000. Digitalis purpurea L. In: Invasive plants of California’s wildlands. Edited by Bossard, C.C., J.M. Randall, and M.C. Hoshovsky. University of California Press. p. 158-161.

7.08

Unknown

8.01

per individual.

(1) http://www.jstor.org.eres.library.manoa.hawaii.edu/stable/pdfplus/4216649.pdf

8.02

(1) Seeds remain viable in the soil at least five years. (2) J. van Baalen's research on germination ecology and seed population dynamics of D. purpurea demonstrated that its seeds have a germination response to light based on contact with soil. Seeds exposed to leaf-filtered daylight remain in the seed bank until a disturbance (such as a windfall) exposes them to soil and daylight.

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php (2) van Baalen, J. 1982 Germination ecology and seed population dynamics of Digitalis purpurea. Oecologia (Berl) 53:61-67

8.03

(1) Herbicide trials were conducted in late summer and early spring by Scott (1997) on infestations of Digitalis lanata in Wilson county, Kansas. Metsulfuron methyl (as Escort®) at label strength and triclopyr (Garlon®) at 2 pts/acre showed some effect on the plants but did not kill all of them. (2) Herbicide trials on Digitalis lanata in Minnesota demonstrated that the most effective and consistent herbicide was Metsulfron methyl (Msm). It eliminated at least 94% of the plants for each application. Msm also provided good residual control of any germinating foxglove seed in all the plots.

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php (2) http://www.dot.state.mn.us/environment/pdf_files/grecian_foxglove.pdf

8.04

(1) Fire associated with other management programs is problematic, since stands of foxglove are not a good fuel source. Also, habitat in which foxglove typically becomes established does not contain enough fuel to sustain a fire long enough to kill the plant. (2) Literature does not mention cultivation or mutilation as a stimulant to growth.

(1) http://www.cal-ipc.org/ip/management/ipcw/pages/detailreport.cfm@usernumber=42&surveynumber=182.php

8.05

None mentioned in the literature