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Western Wetland Flora

Field Office Guide to Plant Species

Seep Spring Arnica
Arnica longifolia D.C. Eat.

JPG -- Species Photo JPG -- Distribution Map

Family: Composite (Compositae)
Flowering: July-August
Field Marks: This Arnica is distinguished by its 5-7 pairs of sessile, toothless leaves on the stem.
Habitat: Around springs, along rivers, wet places in woods.
Habit: Perennial herb with a thickened rootstock and often short rhizomes.
Stems: Up to 2 feet tall, sparsely hairy, some of the stems often not bearing flower heads.
Leaves: Opposite, simple, 5-7 pairs per stem, lanceolate to narrowly elliptic, up to 4 inches long, pointed at the tip, tapering to the sessile or somewhat clasping base, sparsely hairy, usually without teeth.
Flowers: Borne in heads 1-2 inches across, each head consisting of 8-13 yellow ray flowers and several yellow disk flowers; bracts subtending each head long-pointed at the tip, glandular-hairy.
Sepals: 0.
Petals: 5, some united to form yellow rays, others united to form short yellow tubes that comprise the disk.
Stamens: 5.
Pistils: Ovary inferior, smooth or hairy.
Fruits: Achenes elongated, smooth or hairy, with a tuft of tawny hairs at the tip.
Notes: The achenes may be eaten by birds.

Previous Species -- Mountain Arnica (Arnica latifolia)
Return to Species List -- Group 7
Next Species -- Hairy Arnica (Arnica mollis)

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Page Last Modified: Saturday, 02-Feb-2013 06:26:57 EST
Menlo Park, CA [caww55]