Photo: Diane Edwardson, June 20, 2009. This bee's pollen sacs are full. (Click on photo to enlarge.)
UPDATE March 9, 2010: Plant ID via CalFlora, this appears to be a native dandelion.
The Corralitas Red Car Property was a private right-of-way through Silver Lake (Los Angeles) for the Pacific Electric interurban streetcar. The “Big Red Cars” ran until 1955 when the Glendale Line was decommissioned for freeway construction. For more than 40 years, a series of developers tried and failed to develop the Corralitas Red Car Property.
It's not a park, it just looks like one.