Glabrous annual; stems prostrate, freely branched, 1-4 dm, the internodes of the branches very short and the plants thus very leafy; lvs broadly oblong to suborbicular, 2-7 mm, entire; stipules united into a scale-like structure often lobed or fringed at the tip; appendages very small; fr 3-angled, 1-1.5 mm; seeds quadrangular, smooth, 1 mm. Moist alluvial soil; s. Ont. to Mont., s. to Tenn., Fla., Ariz., and trop. Amer., and intr. here and there eastward. July-Oct. (Chamaesyce s.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Herbaceous annuals, stems prostrate and rooting at the nodes, herbage glabrous, plants with milky sap. Leaves: Opposite, cauline, ovate to oblong, and 2-7 mm long with obtuse tips and entire margins, surfaces glabrous, blades short-petiolate with fused, triangular stipules. Flowers: Staminate and pistillate, of radial, flower-like infloresences, involucres obconic, to 1.5 mm long with glabrous surfaces, glands oblong, to 0.5 mm long, with white scalloped appendages wider than the glands, staminate flowers 5-10, generally in 5 clusters around a solitary, central, stalked pistillate flower, each flower a stamen, ovary chambers 3 with 1 ovule per chamber, styles 3, divided half their length, infloresences generally 1 per node. Fruits: Lobed, spheric capsules to 1.5 mm long with glabrous surfaces. Seeds ovoid, white to brown, to 1.5 mm long with smooth surfaces. Ecology: Found in waste and disturbed areas, to 5,000 ft (1524 m). Distribution: Ontario and Montana, south to South America. Notes: Look for this species in Arizona in Santa Cruz county. Etymology: Euphorbia is named for Euphorbus, Greek physician of Juba II, King of Mauretania, and serpens means snake-like. Editor: LCrumbacher2012