Euphorbia paralias
Common names
sea spurge
Biostatus
Exotic
Conservation status
Not applicable
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Detailed description
Erect, ± fleshy, tap-rooted, glabrous, glaucous (sometimes tinged red), perennial herb forming dense swards 0.3–0.7(–1.0 m) tall. Rootstock stout, crown woody, 10–20(–30) mm diam. Stems 1–8(–12), branching from rootstock apex, each divided into 3–5(–10) terminal fertile branches; these dichotomously branched 1–3× again; basal stems woody, bark dark grey to brown; otherwise ± fleshy, pliant, initially glaucous, often maturing reddish-grey to maroon. Leaves fleshy, crowded, closely to loosely imbricate, becoming ± patent with age, increasing in size toward stem apex; lamina (basal) 3.8–4.9(–6.1) × 1.03–2.3 mm, narrowly oblong to obovate-oblong, apex sharply acute, sometimes shortly acuminate, base obtuse, margins entire, adaxially concave, lamina inrolled when dry; lamina (mid stem and upper stem) (6.1–)16.0(–26.2) × (2.4–)3.8(–16.3) mm, obovate-oblong, elliptic-oblong to ovate, apex acute (rarely obtuse), often shortly apiculate, apiculus reddish 0.2–0.4 mm long, base obtuse (sometimes weakly cordate), margins entire; lamina of fertile branches 10.05–14.5(–20.1) × 9.2–13.6(–16.2) mm, suborbicular orbicular, to rhomboid or reniform, apex acute or obtuse, often minutely apiculate, apiculus 0.1-0.3 mm long, base obtuse to weakly cordate, margins entire, adaxially concave. Cyathia solitary, borne in upper forks or terminal; pedunculate, peduncles 0.3–0.5(–10.0) mm long; involucre c.1.5 mm long, yellow-green, campanulate; glands 4, 0.75–1.0 mm long, dull orange to yellow, lunate, emarginate, with 2 short, widely spreading, horns. Male flowers (1–)2–3, sessile or minutely pedicellate, pedicel, 0.01v0.1 mm long, stamen 1, filament 0.1–0.22 mm long; anther 1, 0.2–0.36 mm long, pollen dark yellow. Female flowers solitary, trilocular, each locule bearing one ovule, styles 3, 0.2–1.1 mm long, yellow, each divided into 2 short dark yellow stigmas. Capsule 3.0–5.0 ×4.5–6.0 mm, dark green maturing grey-brown, cartilaginous, depressed-globose, deeply sulcate, keels granulate. Seeds (2.3–)2.5–3.5(–3.6) mm long, pale grey, whitish grey or white, ovoid-globose, smooth, caruncle minute, reniform.
Similar taxa
Superficially similar to the native waiūatua / waiū-o-Kahukura (Euphorbia glauca) which inhabits similar areas but has much larger leaves. Report sightings to Biosecurity NZ on 0800 80 99 66.
Distribution
Exotic. New Zealand: North Island, North Aotea Harbour Heads, Mokau, Himatangi Beach: South Island, North Westland (2020). Indigenous to the Northern Hemisphere (Europe, Mediterranean) species now naturalised throughout South Africa and Australia (Western Australia, South Australia, Victoria, New South Wales and Tasmania)
Habitat
Coastal - on sandy beaches and sand dunes. A strand-line species.
Detailed taxonomy
Genus
Family
Endemic genus
No
Endemic family
No
Other information
Etymology
euphorbia: After Euphorbus, a Greek physician who served King Juba of Numidia in 12BC. Juba named a cactus to honour Euphorbus and later Linnaeus named the entire genus after the physician.
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
Referencing and citations
Attribution
P.J. de Lange 4 May 2012. Description by P.J. de Lange based on New Zealand specimens collected from Aotea Harbour Heads.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Euphorbia paralias Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/euphorbia-paralias/ (Date website was queried)