Virginia Tech Weed Identification Guide

Sun Spurge: Euphorbia helioscopia

sspurge4-8c.jpg (148343 bytes) Weed Description:  A winter annual that grows prostrate along the ground with tips and upper stem portions ascending (decumbent growth habit).  All parts of the plant emit a milky sap when cut.   Sun spurge is a somewhat rare weed of pastures, hayfields, and winter small grains in Virginia.
Stems:  Stout, growing prostrate along the ground with tips ascending.  Stems are distinctly red-tinged and emit a milky sap when cut.  Stems radiate outward from a central point.  Stems may be sparsely hairy, especially in the upper portions. sunspurge3-30G.jpg (61549 bytes)
sspurge3-21e.jpg (184160 bytes) Leaves: The leaves of the upper stem appear whorled but usually occur in groups of 2 or occasionally 3.  Leaves are oppositely arranged along the stem.  Leaves are widest at the apex and taper to the base (oblanceolate).  Leaf apexes are are very finely toothed or serrated.  All leaves generally attach directly to the stem and do not occur on petioles (sessile).
Flowers: Inconspicuous, light green to pale yellow in color.  inflorescences (cyathias) occur at the ends of stems and are 4-lobed.  Each lobe has a round yellowish gland.

Fruit: A very distinctive 3-parted capsule (3-4 mm long) that contains a single, 2 mm long dark brown seed.

sspurge4-8.jpg (41107 bytes)
sunspurge3-21.jpg (166152 bytes) Identifying Characteristics:   The distinctive red stems, leaves with finely toothed leaf apexes, and milky sap are all characteristics that help in the identification of sun spurge.  From a distance, this plant might be confused with Cypress Spurge (Euphorbia cyparissias), which has very similar flowers.   However, the leaves of cypress spurge are much more linear than those of sun spurge and upon closer examination distinguishing between the two species is relatively easy.