Plants in Peril : Environment: A move toward classifying the milk vetch as an endangered species could signal the beginning of a wave of listings in Southern California.

A rare pink-flowered herb found in Southern California, including areas of the Simi Hills in Ventura County, has been proposed by thS. Fish and Wildlife Service for the nation’s endangered species list.

The most immediate threats to the plant--known as Braunton’s milk vetch--are in two canyons slated for development in the Santa Ana Mountains of Orange County. But the plant is also imperiled in the hills above Simi Valley and in the Santa Monica Mountains.

“At almost every place it exists, it’s in jeopardy, primarily from development,” said Tim Thomas, a botanist with the Fish and Wildlife Service’s Ventura field office.

Along with last year’s proposal to place a bird known as the California gnatcatcher on the endangered list, the move toward listing the milk vetch plant could signal the beginning of a wave of listings in Southern California during the next few years.

The agency has proposed adding about 20 Southern California plants to the national list, and final decisions are less than a year away. Among those species, five that are found only in the Simi Hills and the Santa Monica Mountains were proposed for listing at the same time as the milk vetch--the Lyon’s pentachaeta, which is an aster with yellow flowers that grows in grasslands, and four species of dudleyas, which are rare succulents.

Another endangered plant on the list, California Orcutt’s grass, was recently identified near a five-acre seasonal pond in Moorpark--150 miles from the next closest population in San Diego County. The area is targeted for the development of 150 residences.

Another 70 animals and plants-- including a tide-water gobi fish, a red-legged frog and a pond turtle--that are found in Ventura County are not as far along in the process of being included on the endangered-species list. But they are still classified as top candidates.

The Fish and Wildlife Service published its proposal to protect the milk vetch on Nov. 30, and the agency has a year to make a decision. Public comment will be accepted through Jan. 29. Like the gnatcatcher, the milk vetch is granted no federal protection during the review.

No special effort was made to protect the rare milk vetch when Ventura County supervisors approved the Oak Park development in the Simi Hills, Thomas said. The project’s first two phases were completed with little or no buffer space between the endangered plants and the project’s tract homes.

Construction will begin soon on the project’s already approved third phase.

“They destroyed 80% of the milk vetch habitat there, and the remaining population is jeopardized because of the proximity of development to the wild populations,” Thomas said.

A number of milk vetch plants were also destroyed when the Ronald Reagan Presidential Library was constructed and efforts to transplant the herb failed, he said.

Thomas criticized what he called the public’s indifference to the fate of rare native plants.

“As long as you continue to let landscape architects and recreation managers make all the decisions . . . the natural world will take the loss every time,” Thomas said.

State fish and game officials are investigating the apparent destruction last week of some Lyon’s pentachaeta at a site in Thousand Oaks, where the Calleguas Municipal Water District is building a treatment plant.

About one-fourth of the site’s pentachaeta may have been destroyed when the water district bulldozed a road on a neighboring parcel, said Mary Meyer, a fish and game plant ecologist.

Although the loss may have been unintentional, Meyer said the water district could ultimately be required to restore some of the rare aster’s habitat as a penalty.

Rick Burgess, chairman of rare plants for the Channel Islands chapter of the California Native Plant Society, said scientists do not yet understand the role of the milk vetch and Lyon’s pentachaeta in the Southern California ecosystem or the practical value of the plants.

“For instance, we don’t know what type of chemical compounds are in these plants,” Burgess said. “The cure to cancer may be found in plants like this. Like the early ecologist Aldo Leopold said, ‘The first rule of successful tinkering is to keep all the parts.’ ”

When a plant is listed as endangered, private landowners do not have to obtain permits or formally consult with the federal wildlife agency, as they must when an animal is declared endangered. However, they have to document the threat and are encouraged by the federal agency to develop scientifically sound ways to protect the plant.

“Once a plant is listed, they (developers) can’t ignore it,” Thomas said. “It’s just a matter of whether they are willing to try to come up with protection or not.”

Compensating for damage to the milk vetch is more difficult than for many species because it cannot be transplanted and is sensitive to any urban intrusion, according to botanists. The only way to save it, they say, is to leave the land untouched and surround it with a large buffer.

“Nobody knows how to move it to another location,” Thomas said. “It is a plant that absolutely depends on on-site, intact preservation.”

The perennial herb has been considered for the federal endangered-species list for 18 years. But changes in the law and enormous backlogs at the agency delayed the formal listing proposal until development plans in one of the Orange County canyons came to the attention of federal officials.

A member of the pea family, the milk vetch grows only in limestone in mountainous areas lined with chaparral. It can reach five feet tall, and its pointed, fuzzy, gray-green leaves spread into rambling plants with tight clusters of mauve-colored flowers on long stalks.

Its most remarkable characteristic is that it is visible for only about three years following wildfires, which normally occur in intervals of 20 to 50 years. In the meantime, thousands of its seeds lie undetectable and dormant until they are stimulated by the next fire.

Fewer than 300 plants are growing, making it one of the rarest plants found, according to the agency’s proposed rule. Six of its eight remaining populations are jeopardized by recently approved developments, while the others are indirectly threatened, the report says.

“Significant losses” have occurred recently in the Simi Hills and in Santa Ynez Canyon in the Santa Monica Mountains, the federal document says.

Plant in Peril

Common Name: Braunton’s milk-vetch

Scientific Name: Astragalus brauntonii

Range: Three populations remain: in portions of Ventura County’s Simi Hills and Santa Ynez Canyon in Los Angeles County’s Santa Monica Mountains, Orange County’s Coal and Gypsum canyons.

Description: Perennial herb in pea family, with fuzzy, gray-green leaves. Can reach height of five feet. Mauve-colored flowers grow in tight clusters on long stalks.

Habitat: Found among chaparral; grows only in limestone.

Unusual Characteristics: Seeds lie dormant, usually for decades, until they are stimulated by wildfires. Plants then appear for only about three years.

Threats: Plant has always been rare. Now considered on verge of extinction because of development and alteration of normal fire cycles. All known sites unthreatened by new development, including Coal and Gypsum canyons. Only a small part of the plant’s range is on public land, where it is jeopardized by recreational activities.

Nomenclature: This milk vetch is named after Ernest Braunton, who was editor of California Floriculturist. He discovered the plant in 1902 in what is now West Hollywood. The name milk vetch comes from the old belief that goats eating the plant yielded more milk.

Source: U.S. Fish and Wildlife Services.