Wagneriana tauricornis (?) (Orbweaver (nonspecific)).
Size: approx. 5 mm. Photo: 08/19/11, 9 am.

The web span about 1-1.5 m between a small ligustrum and some other plant at a height of 1 m. Most of the time the large spider had its legs curled up and looked like a small leaf or dirt. I'll post more information once I am sure about the identification.  

bug guide (these photos):
J. H Comstock Spider Book (Doubleday: Garden City, New York, 1912, pp. 460):
Bull. Museum Comp. Zool. Harvard Coll. vol. 147: