''Arnica spathulata'' is a rare

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

n species of flowering plant in the family Asteraceae, known by the common name Klamath arnica.Jepson Manual Treatment
/ref> It is native to the Klamath Mountains of northwestern California (

Humboldt Humboldt may refer to: People * Alexander von Humboldt, German natural scientist, brother of Wilhelm von Humboldt * Wilhelm von Humboldt, German linguist, philosopher, and diplomat, brother of Alexander von Humboldt Fictional characters * ...

, Trinity, Siskiyou, and Del Norte Counties) and southwestern Oregon ( Curry, Josephine, Jackson, and Douglas Counties). It grows in woodland habitat, almost exclusively on

serpentine soil Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...

s. ''Arnica spathulata'' 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, and a cluster of leaves about the base of the stem. The basal leaves are up to about 15 centimeters long and the cauline leaves, those higher on the stem, are somewhat shorter. The inflorescence holds many

flower heads A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...

lined with phyllaries coated in long, white hairs. The flower head is discoid, containing only yellow disc florets and none of the showier ray florets. The fruit is an

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

up to a centimeter long, not counting its white pappus.Flora of North America Vol. 21 Page 376 Klamath arnica ''Arnica spathulata'' Greene
/ref>

References

External links

Calphotos Photo gallery, University of California
spathulata Flora of California Flora of Oregon Flora of the Klamath Mountains Plants described in 1896 Taxa named by Edward Lee Greene Flora without expected TNC conservation status {{Asteroideae-stub