

Toothed Spurge Euphorbia dentata
Toothed Spurge is an annual wildflower native to the lower 48 states. It grows to 1.3 ft and blooms Jun – Sep. A host for pollen-specialist native bees.
More about this plant
Euphorbia dentata is a species of spurge known by the common names toothed spurge and green poinsettia. It is native to parts of North and South America, and is present elsewhere on the continents. Its true native range is uncertain. It is a noxious weed in some areas. This is a hairy annual herb with an erect or somewhat erect stem reaching anywhere from 20 to 50 centimeters tall. Its hairy, pointed leaves are a few centimeters long, widely to narrowly lance-shaped, and generally toothed. The inflorescence appears at the end of branches and contain cream or yellowish staminate or pistillate flowers just a few millimeters wide. The fruit is a lobed spherical or heart-shaped capsule about half a centimeter wide which contains three bumpy rounded seeds. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 6 derived from its U.S. range
- Height
- 1.3 ft
- Lifespan
- Annual
- Foliage
- Broadleaf
- Flower colour
- Green AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~7 caterpillar species
Euphorbia supports ~7 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 Euphorbia in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees specialist-bee host · 2 bee visitors
Specialist native bees depend on it.
Some native bees are pollen specialists (oligolectic) — they raise young only on pollen from particular plant genera. Euphorbia is a recorded specialist-bee host, so losing it can mean losing the bee that relies on it.
2 native & managed bee species are documented visiting Toothed Spurge :
Wildlife & visitors 1 bird
Open records of who else uses Toothed Spurge — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 1 bird species (fruit, seed, browse):
How we know this (4) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
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 (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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