

Narrowleaf Arnica Arnica angustifolia
Narrowleaf Arnica is a perennial wildflower native to Alaska, Canada, and Greenland. It grows to 0.2 ft.
More about this plant
Arnica angustifolia is an Arctic and alpine species of plants in the sunflower family, known by the common names narrowleaf arnica and Arctic arnica. It is native to colder regions in Europe, Asia, and North America. It is a perennial herb growing up to 16 inches tall. Its native habitats include bare, rocky slopes and alpine summits. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 6 derived from its U.S. range
- Height
- 0.2 ft
- Lifespan
- Perennial
- Foliage
- Broadleaf
- Flower colour
- Yellow AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts Documented caterpillar host
Recorded feeding on Arnica in North America, including:
✦ Bees 2 bee visitors
2 native & managed bee species are documented visiting Narrowleaf Arnica :
Wildlife & visitors 12 nectaring
Open records of who else uses Narrowleaf Arnica — a generalist food-web signal, kept separate from the keystone Ecological Value.
12 adult butterfly & moth species are recorded nectaring at its flowers — the most-recorded:
How we know this (3) Methods & honest limits
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (22) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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