Ynés Mexía de Reygades, naturalist and botanical collector, daughter of Enrique and Sarah (Wilmer) Mexía, was born in Georgetown, Washington, D.C., on May 24, 1870. Her father, son of Gen. José Antonio Mexía, was a representative at the Mexican consulate in Washington. Her mother was of the family of Samuel Eccleston, fifth Catholic archbishop of Baltimore. In 1871 the family moved to Limestone County, Texas, where they owned an eleven-league grant that became the site of present-day Mexia, Texas. Ynés spent most of her childhood in Texas and received her secondary education in private schools in Philadelphia and Ontario, Canada. She attended St. Joseph's College in Emmitsburg, Maryland, and the University of California, Berkeley. She married Agustín A. de Reygades and moved to Mexico; after their separation, she resumed the use of her maiden name and moved to San Francisco, where she spent the last thirty years of her life. Her interest in botanical collecting began in 1922, when she joined an expedition led by E. L. Furlong, then curator of paleontology at the University of California. Not until 1925, however, did she undertake her first important collecting trip to Mexico. Over the next thirteen years she organized several important expeditions: three trips to Mexico, specifically the states of Sinaloa, Jalisco, Nayarit, Chihuahua, Puebla, Hidalgo, Oaxaca, and Guerrero; one trip to Mount McKinley National Park in Alaska; and two trips to South America. She collected approximately 145,000 specimens, of which 500 were previously undiscovered, and is given credit for two new species.
Mexía traveled alone. Several accounts of her expeditions were published in Madroño (1929, 1935), the journal of the California Botanical Society, as well as in the Sierra Club Bulletin (1933, 1937). She was a well-known lecturer in the San Francisco bay area, where she entertained audiences with tales and photographs of her travels. She was a member of the California Botanical Society, the Sierra Club, the Audubon Association of the Pacific, the Sociedad Geográfica de Lima, Peru, and the California Academy of Sciences; she was also an honorary member of the Departamento Forestal y de Caza y Pesca de Mexico. The Mexía collections can be viewed at the Academy of Natural Sciences, Philadelphia; the California Academy of Sciences, San Francisco; Catholic University, Washington, D.C.; the Field Museum of Natural History, Chicago; Gray Herbarium, Harvard University; the University of California, Berkeley; and important museums and botanical gardens in London, Copenhagen, Geneva, Paris, Stockholm, and Zurich. Mexía's botanical records and personal papers are collected at the Bancroft Library of the University of California, Berkeley. In 1938 she became ill during one of her trips to the mountains of Oaxaca and was forced to return home. She died on July 12 of that year.