Arnica sororia

Arnica sororia
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Genus:	Arnica
Species:	A. sororia
Binomial name
	Arnica sororia; Greene

Arnica sororia is a North American species of arnica known by the common name twin arnica.^[1] It is native to western Canada (British Columbia, Alberta, Saskatchewan) and the western United States (Washington, Oregon, California, Nevada, Utah, Idaho, Montana, Wyoming, South Dakota).^[2] It grows in grasslands and in conifer forests.^[3]

Arnica sororia is a rhizomatous perennial herb producing one or more hairy, glandular stems 10 to 50 centimeters tall. There are several pairs of broadly lance-shaped leaves along the stem, the lower ones borne on petioles. Leaves may reach up to 14 centimeters long.^[4]

The inflorescence holds one to five daisy-like flower heads lined with phyllaries coated in glandular hairs. The flower head has a center of glandular yellow disc florets and a fringe of yellow ray florets. The fruit is an achene a few millimeters long with a white pappus.^[4]

References[]

External links[]

[1] Calflora taxon report, University of California, Arnica sororia E. Greene, twin arnica

[2] Biota of North America Program 2014 county distribution map

[3] Flora of North America Vol. 21 Page 370 Twin arnica Arnica sororia Greene

[q-4] Jump up to: ^a ^b Greene, Edward Lee 1910. Ottawa Naturalist 23(12): 213

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