An Illustrated Guide to ARIZONA WEEDS

The University of Arizona Press



SPURGE FAMILY-Euphorbiaceae

GROUNDFIG SPURGE-Euphorbia prostrata Aiton (E. chamaesyce L.)

DESCRIPTION-A prostrate annual often forming mats, or sometimes partially erect where competing for light, reproducing only by seeds. The pinkish to bright red stems have short, spreading, or curved hairs. The opposite leaves, green or purplish green, are hairless above and thinly hairy beneath, 1/8 to 1/3 inch long, with smooth or finely toothed margins. The 2 scalelike stipules, usually present at the base of the leaf stalks, are lacking or very small and inconspicuous in most species of spurge.

The tiny pinkish flowers, consisting of stamens and pistils only, are grouped into small flowerlike clusters. The 3-lobed seedpods are 1/16 inch or less long, hairy only on the 3 angles, the hairs short and usually stiffly spreading or lying close to the surface on some plants. The oblong seeds, about 1/25 inch long, are sharply 4-angled, and have 6 to 8 sharp cross wrinkles on each face.

DISTRIBUTION-Naturalized from Tropical America, groundfig spurge is one of the worst pests in summer lawns throughout southern Arizona. Also common along paths, roadsides, cracks in sidewalks, streets, gardens, and flower beds; 100 to 5,500 feet elevation; flowering June to November.

PROSTRATE SPURGE-Euphorbia supina Raf.

DESCRIPTION-Very similar to groundfig spurge, but the leaves usually have a red blotch in the center. The stipules at the base of the leaf stalks are branched, threadlike, and about 1/16 inch long. The seedpods and seeds are about the same size, but the hairs lie flat on the surface, and are almost evenly distributed. The seeds have 3 to 5 indistinct cross wrinkles on each face, rather than 6 to 8 distinct ones.

DISTRIBUTION-Introduced from the eastern United States, prostrate spurge is also an aggressive and persistent pest in lawns and flower beds, with the same habitat and general distribution of groundfig spurge.

Copyright (c) 1972 The Arizona Board of Regents

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