Here in Arizona, many people use Lantana as a decorative plant in their yards.  The groundcover thrives in the high temperatures found in the Valley of the Sun.  They also grow in tropical regions.  In my neighborhood, I see them in gold, yellow, red and gold, purple, pink and yellow, and white. 
  
                                           

Unfortunately, the plant contains triterpenoid toxins that harm the liver.  The most common signs in dogs is vomiting and diarrhea.  If enough of the plant is consumed, some will die quickly.  This differs from grazing animals which usually die several weeks later due to a damaged liver.  Ruminants, rabbits, guinea pigs and female rats are all susceptible to this plant.  The red and yellow plants are the most toxic while the white is the least dangerous.  

If you have these plants in your yard, I may have to suggest removing them, fencing them off or using a basket muzzle on your dog to prevent exposure.    

Reference:
Sharma, Om P., et al "A review of the hepatotoxic plant Lantanta Camara" Crit Rev Toxicol, may 2007;37(4):313-52.