Kingdom: Plantae

Phylum: Magnoliophyta -- flowering plants

Class: Magnoliopsida -- dicots

Family: Asteraceae -- sunflower

Common Name: heartleaf arnica

Species Code: ARCO9

Origin: Native to open areas of dry coniferous forest and Populus tremuloides stands of western North America east to North Dakota and New Mexico with disjunct populations in Michigan.

Rare: no

Form: forb

Duration: perennial

Longevity: medium

Habitat Type: forest

Wetland Indicator Status: not listed

Leaves: opposite, cordate, entire to toothed, 4-12 cm long

Mature height: 6-24 inches

Flowers: heads campanulate; ray flowers yellow; disc flowers yellow; involucre densely hairy

Flower color: yellow

Bloom: April, May, June

Bloom starts on: April 29

Bloom ends on: July 7

Fruit: Achene, grey, 5-10 mm long, pappus white.

Characteristics:
A highly variable species (Hitchcock et al 1969).
Reproduces both sexually by seed and vegetatively by rhizomes.
220,000 seeds/lb (USDA NRCS PLANTS Database 2009).
2n=38, 57, 76, 95, 114, 152, ±198 (Baldwin et al 2004).
2n=38, 57, 76, 95, 114 (Flora of North America Editorial Committee 1993).
x=19 (University of British Columbia 2003).
Apomixis is common in the genus. Diploids of Arnica spp. usually form seeds sexually while polyploids are mostly apomictic (Baldwin et al 2004).
Ray flowers are pistillate, disc flowers are complete.
Multiple ploidy levels are known.
Plant is poisonous but has medicinal properties.
Fruit is an achene.
Mule deer occasionally graze the plants (Craighead et al 1969). Rocky Mountain elk graze the plants in summer (Kufeld 1973).
Seeds are probably dispersed short distances by wind.

Sun requirement: shade tolerant

Soil moisture: moist

Precipitation: 10-35 inches (USDA NRCS PLANTS Database 2009).

Fire: Sprouts from surviving rhizomes and seed blown in from surrounding areas. Easily killed by moderate to high intensity fires but better able to survive low intensity fires (Reed 1993).
3-7 years to recover fully from fire (Patterson et al 1985).
Arnica cordifolia is susceptible to fire because the roots and rhizomes are near the surface of mineral soil (McLean 1969).

Hazards: poisonous

Sowing time: fall

Transplant time: spring

Stratification: cold moist

Seed size: 5-10 mm long

Herbaria: Specimen data and digital resources from The Consortium of Pacific Northwest Herbaria

Remarks:
Propagation:
1 protocol on the Native Plant Network
Glacier National Park, MT

Other Propagation Information:
Stratification is required for seed (Kingery et al 2003).
For a Yellowstone National Park ecotype, Romme et al (1995) found nearly 75% of the seed was not filled and most of the filled seed was either nonviable or weakly viable.
Reproduces both sexually by seed and vegetatively by rhizomes.

References:
Baldwin, B.G., S. Boyd, B.J. Ertter, D.J. Keil, R.W. Patterson, T.J. Rosatti, and D.H. Wilken (eds). 2004. Jepson Online Interchange for California Floristics. University and Jepson Herbaria, University of California, Berkeley, CA. Accessed 7/23/09 online at http://ucjeps.berkeley.edu/interchange.html

Craighead, John J., Frank C. Craighead, and Ray J. Davis. 1963. A Field Guide to Rocky Mountain Wildflowers. Boston, MA. Houghton Mifflin Co.

Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 7+ vols. New York and Oxford. Oxford University Press. Online at http://www.fna.org/FNA/

Hitchcock, C. Leo, Arthur Cronquist, Marion Ownbey, and J.W. Thompson. 1969. Vascular Plants of the Pacific Northwest. University of Washington Press. Seattle, WA. Vol. 5, Asteraceae.

Kingery, James, Angela Cotter, and Kendra Moseley. 2003. Idaho Roadside Revegetation Handbook. Prepared for: Idaho Transportation Department. Department of Rangeland Ecology and Management, University of Idaho. Online at http://h237-41.state.id.us/highways/ops/maintenance/Manuals/fullVegetationManual.pdf

Knapp, A.K., W.K. Smith, and D.R. Young. 1989. Importance of Intermittent Shade to the Ecophysiology of Subalpine Herbs. Functional Ecology 3:753-758.

Kufeld, Roland. 1973. Foods Eaten by the Rocky Mountain Elk. Journal of Range Management 26:106-113.

McLean, Alastair. 1969. Fire Resistance of Forest Species as Influenced by Root Systems. Journal of Range Management 22:120-122.

Patterson, Patricia A., Kenneth E. Neiman, and Jonalea R. Tonn. 1985. Field Guide to Forest Plants of Northern Idaho. USDA Forest Service Intermountain Research Station. General Technical Report INT-180. Ogden, Utah.

Reed, William R. 1993. Arnica cordifolia. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2008, February 4].

Romme, William H., Laura Bohland, Cynthia Perischetty, and Tanya Caruso. 1995. Germination Ecology of Some Common Forest Herbs in Yellowstone National Park, Wyoming, USA. Arctic and Alpine Research 27:407-412.

USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 13 July 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

University of British Columbia. 2003. British Columbia Flora. University of British Columbia Botanical Garden and Centre for Plant Research. Online at http://www.bcflora.org/ Accessed 1/1/06.

Young, Donald R., and William K. Smith. 1980. Influence of Sunlight on Photosynthesis, Water Relations, and Leaf Structure in the Understory Species Arnica cordifolia. Ecology 61:1380-1390.

Young, Donald R., and William K. Smith. 1982. Simulation Studies of the Influence of Understory Location on Transpiration and Photosynthesis of Arnica cordifolia on Clear Days. Ecology 63:1761-1770.

Links:

Plant Profile from the USDA PLANTS Database
Species account from the US Forest Service Fire Effects Information System
Species description from Flora of North America
Species information from the University of Washington Herbarium