The tiny yellow sunflower known as Lyon's pentachaeta, with its dime-sized blossoms atop toothpick-thin stems about six inches tall, would not seem much of an obstacle for bulldozers.
But the diminutive plant, part of the sunflower family, has blocked construction projects ranging from the Ronald Reagan Presidential Library to a golf course.
Continuing its career as a bulldozer-blocker, the tiny flower is now the basis of an effort by the Santa Monica Mountains Conservancy to block construction of 51 houses on a remote hillside of Westlake Village.
Lyon's pentachaeta (named after a turn-of-the-century Los Angeles botanist named Lyon) is listed by the state as an endangered species and survives only in 10 sites scattered through the Santa Monica Mountains.
Indigenous to California, the flower was discovered in San Pedro and on Santa Catalina Island during the 1890s but apparently has died out except in the mountains.
In an effort to stop the planned housing development amid one of the largest known fields of Lyon's pentachaeta, the state attorney general's office filed a lawsuit this week against Westlake Village, citing alleged violations of the California Environmental Quality Act by the city in its approval of the proposed Lake Eleanor Hills development.
The conservancy estimates that the project would wipe out 90% of the 1,000 sunflowers on the property and also endanger wildlife and American Indian artifacts.
The city and developer M. J. Brock & Sons say that they have never forgotten the flower during their months of planning for the project.
For instance, 3 1/2 acres have been set aside in an area where significant concentrations of the blossoms were found, they say.
"We consider ourselves to be good neighbors," said David Kitnick, land acquisitions manager for M. J. Brock & Sons.
Although there have been clashes over Lyon's pentachaeta in the past, this is the first battle since the flower received protected status a year ago, said biologist Tim Thomas, who petitioned the state to put the plant on its endangered list.
"There are more and more developments that are affecting these plants," said Thomas, who is rare-plant chairman of the California Native Plant Society's local chapter. "Botanists in the region are aware of this plant and record when they find it. There are fewer and fewer discoveries.
"It's faced with elimination from the landscape. The quality of human existence can only be poorer if we lose this species. It can only be richer if we save them."
Those fighting to save Lyon's pentachaeta grant that it may lack the grandeur of a bald eagle or giant oak tree.
But endangered species, environmentalists say, shouldn't be judged that way.
"I think it's a rather pretty flower, but it isn't all that beautiful," said Kent Schwarzkopf, a planning analyst for the conservancy. "But the issue is not how beautiful or big it is. It's a very rare plant and we want to do what we can to save it."
The plant is so rare and blooms so infrequently that it was almost overlooked in Westlake Village.
The draft environmental impact report by a consultant to the builder, prepared in the fall when the plants are not in bloom, did not mention the plant. A follow-up did.
Mayor Ken Rufener said he had not even heard of Lyon's pentachaeta until last year.
When he and his wife moved to Westlake Village in 1967, they were the 22nd family to arrive.
With a population of more than 8,000 now, the city has once-unheard-of problems, such as traffic congestion.
"The flower, really, in my eyes, is not an attractive flower," said Rufener, 71, a retired Air Force officer. "It's only as big as the tip of my little finger and it looks like the flowers you see all along the freeways. Those, in fact, are more attractive."
Nonetheless, Rufener said, he realizes that it is an endangered species, and he says the city did everything it could to protect the flower.
He said the 74-acre development site at the southern end of Westlake Village was originally zoned for 90 single-family houses.
The developer proposed a 56-house development last year. That number was whittled to 51 when the City Council approved the plan last month, with one site eliminated to preserve a hillside view and four sites eliminated for Lyon's pentachaeta.
The city also required the developer to save all but four of the 90 oak trees on the site and submit a proposal to the state Fish and Game Commission on ways it planned to mitigate loss of the flowers.
It was a state-approved mitigation plan that allowed Reagan to build a Spanish colonial-style library in Simi Valley, despite the nine large patches of the plant found near the site of a mile-long, 60-foot-wide road to the library.
The 1988 mitigation plan forced the Ronald Reagan Presidential Foundation to replace the flowers it bulldozed and to put up fences to shield the other plants.
Lyon's pentachaeta popped up again last year at the Lake Sherwood Country Club, where developers were required to extract plant seeds so the endangered plant could be grown at other sites.