

Dwarf Scouringrush Equisetum scirpoides
Dwarf Scouringrush is a perennial horsetail native to Alaska, Canada, and Greenland.
More about this plant
Equisetum scirpoides Michx., Fl. Bor.-Amer. 2: 281 (1803). 2 n = 216. The smallest of the currently occurring representatives of the genus Equisetum (horsetail). Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 4 derived from its U.S. range
- Lifespan
- Perennial
- Foliage
- Evergreen microphyll
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~1 caterpillar species
Equisetum supports ~1 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a modest genus.
Recorded feeding on Equisetum in North America, including:
Wildlife & visitors 1 bird
Open records of who else uses Dwarf Scouringrush — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 1 bird species (fruit, seed, browse):
Across 69 U.S. vegetation-survey plots that recorded Dwarf Scouringrush, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.
How we know this (2) 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.
Sources for this entry (23) 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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