Botanical name: Euphorbia peplus.
Common names: Petty spurge, radium weed, milkweed or cancer weed.
Life cycle: Annual
Growth period: Warm season
Preferred habitat: It seems to be able to grow in very shallow soil. I've seen it growing in the cracks of pavers. Petty spurge seems to like good friable soil as opposed to rocky wasteland. It likes lots of sun.
Root system: Fibrous
Size: 5 - 30cm tall
Physical characteristics: Small ovate leaves and green flowers. Milky latex sap when cut.
Physical control: Hand removal or burning
Cultural control: Mulching will keep Petty spurge down for a while but not for long. Petty spurge is a strong competitor so crowding it out with other plants may not be successful.
Reproduction methods: Petty spurge can reproduce by seed if left long enough. It can also propagate itself by vegetative spread (ie parts of the plant that are broken off and left on soil can form into new plants).
Chemical control: Glyphosate can destroy Petty spurge but it is an easy weed to remove by hand so chemical control may not be suitable depending on the level of weed infestation.
Friend or Foe? An interesting fact about Euphorbia Peplus is that it's toxic to rapidly reproducing human tissue. It has been used as a herbal remedy for skin lesions including skin cancer. The method for this treatment is to rub the white latex sap of the affected area of skin. The active ingredient in the sap is actually used in some pharmaceutical products for skin problems.