Occasionally plants show up in our office for identification and no one in the office knows what it is.  So it's sent off to to others who might know.  This was the case of a perennial amaranth, also called goosefoot for some reason. The is Chenopodium californicum, also know as Blitum californicum. 

Like other amaranths, it can be upright to 3 feet in height, or if mowed or grazed be more flattened or decumbent.  It has a thick, fleshy stem that along with the leaves can be eaten. I guess pigs like it, because it's also called pigweed.

The leaves look sort of lettuce like, which gives it another name - Indian Lettuce.

The stem has also been used for making soap, which gives it another name of soaproot.  Which is not to be confused with another soaproot, Chloragulum. Plant names can be confusing.

Chenopodium californicum, Blitum,goosefoot, pigweed, soaproot grows in the chaparral on slopes and in foothill woodlands, mainly along the coast.

Calflora: http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=1968

Plants for a Future: https://www.pfaf.org/USER/Plant.aspx?LatinName=Chenopodium+californicum