Hi, your first photo, the one with a closeup of the seedhead, is kind of blurry. Seeing the seedhead clearly could help a lot in identifying your weed.

Donn, Beautiful seedheads. Can't remember whether I've ever tried this specific grass but most I've easily dried just standing in container (no water) in dark place with good ventilation. The heads will retain their lovely curve this way. If you liked you could hang upsidedown by the stems and heads will dry straight and, depending on how sturdy the stems are, may remain that way. You can strip off leaves or leave on but they may curl as they dry. Just depends on effect you want. One of my books suggests laying grasses out on newspaper to dry to better retain shape of leaves. I've never tried this. Good luck. I hope one of the professional growers will reply. josh (just enthusiastic amateur)

here are few more photos these are in my backyard. seem like the same plant. 1st one is 7 inches tall and the other 2 photos seems like the same plant but fully matured.

Southern California??? Is that La Jolla, Mt Baldy, or Heber? It has to be one of those places because those are the only places in SoCal. Seriously there are far too many micro climates in the region to give solid suggestions. Can you please home in on a location? And saying, "Los Angeles," or "San Diego," is almost as bad. Those are small geographical locations, but people who live in El Monte or El Cajon insist on claiming the more general title. We're not coming over for dinner, so be somewhat specific. I'm going to suggest it could be St Augustine, centipede, or kikuyu grass. Due to the extreme coarseness I'm leaning toward kikuyu. There's a lot of it all over SoCal. St Aug will grow in almost any soil. Centipede practically insists on acidic soil. Kikuyu will grow anywhere, also, but it is much, much more aggressive than St Augustine. Here is a picture of centipede (on top) and St Augustine. Note that centipede has pointed tips on the blades while St Aug has blunt tips. Here is a picture of kikuyu growing over a road.