Ynés Enriquetta Julietta Mexía (May 24 1870 – July 12 1938) was a Mexican-American botanist notable for her extensive collection of novel specimens of flora and plants originating from sites in Colombia, Mexico, and Peru.

She discovered a new genus of Asteraceae, known after her as Mexianthus, and accumulated over 150,000 specimens for botanical study[1] over the course of a career spanning 16 years enduring challenges in the field that included poisonous berries, dangerous terrain, bogs and earthquakes for the sake of her research.

[8][9][5] Around the time of his death, Mexia started Quinta, a pet and poultry stock raising business, at the hacienda she inherited from her father's estate.

[11][5][12][10] In 1909, at the age of 39, Mexía suffered a mental and physical breakdown and left Mexico for San Francisco in search of medical care.

[14] While in Northern California, Mexía began going on excursions with the Sierra Club into the mountains, and thus became interested in the region's ecology such as redwoods, birds, and plants.

Her habits often surprised people she met because she was not acting in a manner typical of a woman of the early 20th century: traveling alone, riding horseback, wearing trousers (knickers), and preferring to sleep outside even if beds or indoor accommodations were available.

[2] She wrote about her rejecting of such stereotypes and commented that "A well-known collector and explorer stated very positively that 'it was impossible for a woman to travel alone in Latin America,'"[2] and emphasized that "I decided that if I wanted to become better acquainted with the South American continent the best way would be to make my way right across it.

Forced to abort the trip and return to the United States, she was subsequently diagnosed with lung cancer and died a month later at the age of 68.

[2] William E. Colby, then secretary of the Sierra Club, wrote "All who knew Ynés Mexía could not fail to be impressed by her friendly unassuming spirit, and by that rare courage which enabled her to travel, much of the time alone, in lands where few would dare to follow".

[2][12] Mexía began her career in botany in 1922 when she joined an expedition led by Mr. E. L. Furlong, the Curator of Paleontology at University of California, Berkeley.

Her specimens are housed at the California Academy of Sciences (main collection), the Academy of Natural Sciences, Philadelphia, the Field Museum of Natural History, the Gray Herbarium, the New York Botanical Garden, the Smithsonian Institution, the University of California, Berkeley, and the U.S. National Arboretum, as well as several museums and botanical gardens throughout Europe.

[2] Vassiliki Betty Smocovitis, a professor of the history of science at the University of Florida, explains that:"Women were actively dissuaded from doing that kind of work, because it was considered unfeminine and dangerous," says .

[19][23] Mexía is remembered by her colleagues for her expertise in fieldwork, resilience in the face of difficult and dangerous conditions, as well as her impulsiveness and fractious but generous personality.

[2] Mexía provided funding for Vernon Orlando Bailey to create and produce his pioneering invention of more humane traps for animals.