Flora of the Hawaiian Islands
Dicotyledon Literature for Euphorbia prostrata
Wagner et al., 1990, 1999; Lorence & Wagner, 2020.
   Euphorbiaceae -- The Spurge Family Bibliography
      Euphorbia prostrata

Common name(s): spurge, prostrate spurge
General Information
DistributionNative from southern United States to South America, the West Indies, and the Paleotropics.In the Hawaiian Islands, naturalized on Midway, Ni`ihau, Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Kaho`olawe, Hawai`i.

Mat-forming annual herb; stems 7–20 cm, often purplish, prostrate, crisp pubescent to pilose or sometimes glabrate.
Leaves distichous, slightly unequal; blade oblong to ovate-oblong, 3–9 mm long, 1.5–5 mm wide, sparsely pubescent or sometimes glabrate, margin serrate, apex rounded or obtuse, base rounded; petiole 0.5–1 mm long; stipules ± distinct, linear lanceolate, 1–2 mm long, ciliate.
Cyathia solitary at nodes of short, congested, leafy, lateral shoots; involucre purple, 0.4–0.7 mm high, sparsely villous or glabrous, glands 4, maroon, suborbicular, 0.05–0.15 mm long, appendages minute, pinkish white, shorter than the gland is wide. Staminate flowers 2–5 per cyathium.
Fruit ovoid, 3-angled, 1–1.4 mm long, pilose on the angles, otherwise glabrous.
Seeds gray to tan, narrowly ovoid, strongly 4-angled, ca. 1 mm long, faces strongly ridged.
2n = 18, 20.
Nancy Khan