The last major remnant of the Los Angeles Coastal Prairie was a portion of a 300-acre site destroyed as habitat in the late 1960s. Unfortunately the unique community was lost before it could be thoroughly studied. The substrate, which defined the prairie, was consolidated sand of the pre-Flandrian sand dune formation established during the Pleistocene. The prairie covered about 36 square miles, extending north-south from the crest of the Ballona Bluffs to Palos Verdes and inland from the lee of the El Segundo sand dunes for three to six miles. The area was rich with vernal pools and some marshy areas. It was renowned for spectacular wildflower displays. The historical plant community of the prairie is reconstructed using herbarium records and historical sources and illustrated using anecdotal records.
Lay people have long recognized the unique character of the Los Angeles Coastal Prairie. The plains rolling to the sea are described in many travelers' accounts of early Los Angeles (Brewer 1930). Historian Roy Rosenberg writes of the time before the prairie was converted from ranching to dry farming in the 1800s by Inglewood founder Daniel Freeman:
[I]t is recorded that the Freeman children rode over the rancho through fields of wildflowers that extended to the Pacific. The sight of these great fields, suddenly confronting a person as he neared the top of Baldwin Hills, brought as enthusiastic exclamations of surprise and wonder from his lips as does the present panorama which greets the traveller as he speeds over ribbons of concrete enroute from the metropolitan district to Inglewood. Where once grew wild flowers with abandon -- poppies, lupin, mustard, horseradish and verbena -- there now appears a sea of lights which that great raconteur, Alexander Wolcott, has aptly likened to "the babel of a million tungstens" (Rosenberg 1938:12-13).
A Manhattan Beach resident wrote of his childhood in the 1920s:
While living at 3116 Alma, we almost always walked to school. We walked over the sanddunes, through the area where Grandview School is located, across the fields, over the railroad tracks, past the Catholic Church property. Quite often we would pick wild flowers like Lupins, Indian Paint Brush, and mustard flower, which grew everywhere, to take to our teachers (Dow 1976:27).
Although the landscape that inspired it is now largely gone, there remains a Prairie Avenue in Inglewood.
Based on a map developed by Cooper (1967) for his comprehensive review of the coastal sand dunes of California, this map shows the extent of the prairie and its vernal pools. The prairie was defined edaphically by pre- Flandrian dunes, which coincide with the Oakley Sand formation shown by the U.S. Bureau of Soils survey (Nelson 1919). The undrained vernal pools were presumably created by coastal ridges degraded over time. To the south, the prairie was bounded by the Palos Verdes uplift and an extensive marsh system. To the east the Torrance plain was characterized by sage scrub, while the northern boundary was formed by the Ballona Bluffs. The western edge of the prairie was the actively flowing Flandrian sand dunes along the immediate coast. In contrast, the sand of the earlier dune system, created during the 80,000 years prior to the last glaciation, had become more or less consolidated, presenting the soil conditions that defined the prairie. The enormous quantities of sand contained in both dune systems was provided by alluvial sand carried by Ballona Creek, which until the 1800s was fed by the Los Angeles River.
Photo of Prairie Floor, 1938
Photo of Vernal Pool
Photo of Prairie in Summer