Question: Which President that served as a Senator from California,  did Beatrice Willard serve as an advisor?

full_context: Document 1: Mary Bowerman: Mary Leolin Bowerman (January 25, 1908 – August 21, 2005) was an American botanist, co-author of "The Flowering Plants and Ferns of Mount Diablo, California; Their Distribution and Association into Plant Communities""," and the co-founder of Save Mount Diablo. She helped to preserve tens of thousands of acres of Mount Diablo in the San Francisco East Bay before dying at age 97. In 1936 she was the last person to record the Mount Diablo buckwheat "Eriogonum truncatum," until it was rediscovered nearly seventy years later on May 10, 2005. In 1978 the manzanita "Arctostaphylos bowermaniae" was named in her honor.
Document 2: United States vice presidential selection, 1973: In 1973, Republican Vice President Spiro Agnew was forced to resign following a controversy over his personal taxes. Under the terms of the 25th Amendment, a vice presidential vacancy is filled when the president nominates a candidate who is confirmed by both houses of Congress. Republican President Richard Nixon thus had the task of selecting a vice president who could receive the majority support of both houses of Congress. Nixon considered selecting former Texas Governor John Connally, New York Governor Nelson Rockefeller, and California Governor Ronald Reagan. However, Nixon settled on House Minority Leader Gerald Ford of Michigan, who was popular among the members of Congress and who was good friends with Nixon. Ford won the approval of both houses by huge margins, and was sworn in as the 40th Vice President of the United States on December 6, 1973. In 1974, Ford ascended to the presidency after the Watergate scandal led to the resignation of President Nixon.
Document 3: Gerald Ford: Gerald Rudolph Ford Jr. (born Leslie Lynch King Jr.; July 14, 1913 – December 26, 2006) was an American politician who served as the 38th President of the United States from August 1974 to January 1977, following the resignation of Richard Nixon. Prior to this he served eight months as the 40th Vice President of the United States, following the resignation of Spiro Agnew. He was the first person appointed to the vice presidency under the terms of the 25th Amendment, and consequently the only person to have served as both Vice President and President of the United States without being elected to executive office. Before his appointment to the vice presidency, Ford served 25 years as U.S. Representative from Michigan's 5th congressional district, the final nine of them as the House Minority Leader.
Document 4: United States vice presidential selection, 1974: In 1974, Republican President Richard Nixon was forced to resign following the Watergate Scandal. Vice President Gerald Ford ascended to the presidency, leaving the office of vice president vacant. Under the terms of the 25th Amendment, a vice presidential vacancy is filled when the president nominates a candidate who is confirmed by both houses of Congress. On August 20, 1974, Ford announced his nomination of former New York Governor Nelson Rockefeller to fill the vacancy. Ford also considered picking Tennessee Senator Howard Baker and former Republican National Committee Chairman George H.W. Bush. Rockefeller was generally considered to be a liberal Republican, and Ford decided that picking Rockefeller would help his candidacy gain support in the 1976 presidential election. The confirmation hearings for Rockefeller lasted for months, but Rockefeller was sworn in as the 41st Vice President of the United States on December 19, 1974. Due to the pressure on Ford by the party conservatives, Rockefeller was ultimately passed over for the 1976 ticket, and Ford instead chose Bob Dole as his running mate. Ford, however, regreted this move later.
Document 5: Beatrice de Cardi: Beatrice Eileen de Cardi, {'1': ", '2': ", '3': ", '4': "} (5 June 1914 – 5 July 2016) was a British archaeologist, specializing in the study of the Persian Gulf and the Baluchistan region of Pakistan. She was president of the British Foundation for the Study of Arabia, and she was Secretary of the Council for British Archaeology from 1949 to 1973. At the end of her career, she was the world's oldest practising archaeologist.
Document 6: Richard Nixon: Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th President of the United States from 1969 until 1974, when he resigned from office, the only U.S. president to do so. He had previously served as the 36th Vice President of the United States from 1953 to 1961, and prior to that as a U.S. Representative and also Senator from California.
Document 7: Lady Bird Johnson Wildflower Center: The Lady Bird Johnson Wildflower Center is a public botanical garden dedicated to creating a more sustainable earth through research and education. Situated 10 miles southwest of downtown Austin, Texas and just inside the edge of the distinctive Texas hill country, the 279-acre Wildflower Center attracts 100,000 annual visitors. The center is a self-supporting research unit of The University of Texas at Austin devoted entirely to native plants, with more than 700 species native to central Texas, and the environmental benefits of native-plant landscaping. (see Native Plant Information Network). The Wildflower Center also hosts changing exhibits of visual art and photography and features outdoor sculptures, walking trails, formal and research plantings, educational exhibits, and an annual sale of native plants. In 2013, the syndicated television series, "Texas Country Reporter", hosted by Bob Phillips, declared the center the No. 1 site from which to view wildflowers within Texas.
Document 8: Gerald Ford: Gerald Rudolph Ford Jr. (born Leslie Lynch King Jr.; July 14, 1913 – December 26, 2006) was an American politician who served as the 38th President of the United States from August 1974 to January 1977, following the resignation of Richard Nixon. Prior to this he served eight months as the 40th Vice President of the United States, following the resignation of Spiro Agnew. He was the first person appointed to the vice presidency under the terms of the 25th Amendment, and consequently the only person to have served as both Vice President and President of the United States without being elected to executive office. Before his appointment to the vice presidency, Ford served 25 years as U.S. Representative from Michigan's 5th congressional district, the final nine of them as the House Minority Leader.
Document 9: Richard Nixon: Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th President of the United States from 1969 until 1974, when he resigned from office, the only U.S. president to do so. He had previously served as the 36th Vice President of the United States from 1953 to 1961, and prior to that as a U.S. Representative and also Senator from California.
Document 10: Jane Colden: Jane Colden (March 27, 1724 – March 10, 1766) was an American botanist, described as the "first botanist of her sex in her country" by Asa Gray in 1843. Although not acknowledged in botanical publications, she wrote a number of letters resulting in botanist John Ellis writing to Carl Linnaeus of her work applying the Linnaean system of plant identification to American flora, "she deserves to be celebrated". Contemporary scholarship maintains that she was the first female botanist working in America. She was regarded as a respected botanist by many prominent botanists such as: John Bartram, Peter Collinson, Alexander Garden, and Carl Linnaeus. Colden is most famous for her manuscript which remains titleless, in which she describes the flora of the New York area, and draws ink drawings of 340 different species of them.
Document 11: White House Vegetable Garden: The White House has had multiple vegetable gardens since its completion in 1800. Eleanor Roosevelt, Hillary Clinton and Michelle Obama all have had their own versions of vegetable gardens. Roosevelt planted the White House victory garden during World War II to promote the use of victory gardens by American citizens in a time of possible food scarcity. Hillary Clinton had a vegetable garden constructed on the roof of the White House. On March 20, 2009 Michelle Obama broke ground on the largest and most expansive vegetable garden to date on the White House lawn.
Document 12: Beatrice Willard: Beatrice Willard (December 19, 1925 – 7 January 2003) was an American botanist who specialized in studies on the ecology and botany of high alpine tundra, as well as arctic tundra. Willard's studies influenced public policy with her studies, which centered on plant life at high altitudes. Willard was responsible for the establishment of the Beatrice Willard Alpine Tundra Research Plots above the treeline in Rocky Mountain National Park, now listed on the National Register of Historic Places. In later years she was an adviser to U.S. presidents Nixon and Ford as the first woman on the Council on Environmental Quality (CEQ).
Document 13: Electoral history of Richard Nixon: Electoral history of Richard Nixon, 37th President of the United States (1969–1974), 36th Vice President of the United States (1953–1961); United States Senator (1950–1953) and United States Representative (1947–1950) from California.
Document 14: Beatrice Willard Alpine Tundra Research Plots: The Beatrice Willard Alpine Tundra Research Plots were established in 1959 along Trail Ridge Road in Rocky Mountain National Park, Colorado, above the treeline in an alpine tundra habitat. The plots were used by Beatrice Willard of the Institute of Arctic and Alpine Research at the University of Colorado from 1959 to about 1999 in a long-term study of the alpine ecosystem. Willard's dissertation and updates, as well as her book "Land Above the Trees: A Guide to American Alpine Tundra" were highly influential in studies of alpine and tundra ecology. Her recommendations were used by the National Park Service in its management of the high alpine areas of the park. Willard's work continued after she moved on to other work, and for the last twenty years she made informal visits to the plots.
Document 15: J. Baird Callicott: J. Baird Callicott is an American philosopher whose work has been at the forefront of the new field of environmental philosophy and ethics. He is a University Distinguished Research Professor and a member of the Department of Philosophy and Religion Studies and the Institute of Applied Sciences at the University of North Texas. Callicott held the position of Professor of Philosophy and Natural Resources at the University of Wisconsin–Stevens Point from 1969 to 1995, where he taught the world’s first course in environmental ethics in 1971. From 1994 to 2000, he served as Vice President then President of the International Society for Environmental Ethics. Other distinguished positions include visiting professor of philosophy at Yale University; the University of California, Santa Barbara; the University of Hawai’i; and the University of Florida.
ground_truth: Richard Milhous Nixon