The Botanizing Presidential Candidate

The Missouri Botanical Garden is home to more than seven million plant specimens. In addition to its role as a research tool for botanists, it is also a window into history. Each specimen tells a story—connecting people, plants, and places. The Garden’s herbarium can tell us about the early career of groundbreaking botanist George Washington Carver, the adventures of naturalist John Muir, and the scientific exploration of Alaska.

It also provides a window into the botanizing escapades of the first Republican candidate to run for president of the United States—John Charles Frémont.

Who is John Frémont?

Frémont is quite a historical character, with some strong ties to St. Louis and Missouri. To run through just a few highlights:

  • He earned the nickname “The Pathfinder” for leading five expeditions throughout the American west. These include explorations of the Rocky Mountains and Sierra Nevada range, and a mapping of the entire length of the Oregon Trail. There are peaks in California, Wyoming, Colorado, and Arizona named in his honor, along with a river in Utah.
  • Frémont eloped with 17-year-old Jesse Benton, the daughter of powerful Missouri politician Thomas Hart Benton.
  • Frémont was appointed military governor of California, only to be forcibly removed and court martialed three months later. He would later have a brief stint as one of the state’s first two U.S. Senators. The city of Fremont, California, is named in his honor.
  • Due in part to his opposition to the Fugitive Slave Act, Frémont was nominated by the newly formed Republican party as its first presidential candidate in 1856. He would lose to Democrat James Buchanan.
  • He was given command of the Union’s western forces during the Civil War, based out of St. Louis. He lost Springfield, Missouri, to confederate forces only to retake the city a few months later. He was relieved of his post after only four months.
  • During his leadership of the western forces, Frémont declared martial law and attempted to emancipate all enslaved people held by rebels in Missouri. He would be rebuked by President Abraham Lincoln, who would issue his own Emancipation Proclamation a year later.
  • Frémont was appointed Governor of Arizona in 1878, only to resign from office after three years for refusing to spend time in the state.

The above highlights don’t even cover Frémont’s role in the California Gold Rush, his brief time as a Missouri railroad baron, or his second, short-lived stint as a presidential candidate for the Radical Democracy Party.

Prolific Plant Collector

While his political and military records may grab your attention, it could be argued Frémont’s biggest contribution to history was his prolific collecting of plants.

His plant collecting in the 1840s and 1850s led to the discovery of 157 new species, and 19 new genera. Nearly two dozen of those species bear his name, from a towering poplar tree (Populus fremontii) to several members of the daisy family (among them Layia fremontii). A genus of flowering shrubs, Fremontodedron, is also named after him.

The Garden holds more than 150 plant specimens collected by Frémont during his expeditions. They were originally part of the personal herbarium of St. Louis doctor George Engelmann, who was an advisor to Garden founder Henry Shaw. The specimens give us a botanical roadmap of Frémont’s explorations of the west.

The type specimen for Cuscuta californica var. graciliflora, collected by Frémont in 1846 and described as a new species by George Engelmann.

First Expedition (1842)

After outfitting the expedition in St. Louis, Frémont and his crew left Kansas City in June of 1842. They would follow the Platte River through Nebraska and explore the Wind River Range of the Rocky Mountains in Wyoming. Collections from that trip held in the Garden Herbarium include several species of alpine grasses and a pleated gentian.

Left: Gentiana affinis collected by Frémont in 1842. From the Garden Herbarium.
Right: Gentiana affinis at Bergian Garden in Stockholm, Sweden. By Rolf Engstrand for Wikimedia Commons.

Second Expedition (1843-44)

Frémont’s second expedition followed the Oregon Trail to the Columbia River and Cascade Mountains in Oregon before turning south to explore the Sierra Nevada Mountains and the Great Basin.

Although many of Frémont’s specimens only denote the year, those with more specific dates give us some insights into the trip. For instance, a collection of saltgrass (Distichlis spicata) from September 1843 coincides with the expedition’s approach to Great Salt Lake. And in May of 1844 Frémont collected a new species of legume that would later bear his name — Psorothamnus fremontii — as the expedition left Las Vegas.

Left: Psorothamnus fremontii collected by Frémont. From the Garden Herbarium.
Right: Psorothamnus fremontii in Red Rock Canyon, Nevada. By Stan Shbs for Wikimedia Commons.

Third Expedition (1845-46)

The largest number of Frémont specimens held in the Garden Herbarium are from the third expedition. While on its surface the expedition was one of discovery, there were also strategic political and military reasons for sending Frémont west. The United States was on the brink of war with Mexico for control of much of the present-day American Southwest.

Frémont’s collections in 1845 focused on the Great Basin region, before heading to California where he would play a role in instigating conflict with the Mexicans (while still collecting plants). Among the new species based on his collections from this expedition are the California flannelbush, Fremontodendron californicum.

Left: A type specimen of Fremontodedron californicum collected by Frémont. From the Garden Herbarium.
Right: Fremontodendron californicum in San Jose, California. By Eugene Zelenko for Wikimedia Commons.

What’s in a Name?

It should be noted that while Frémont was credited with discovering many plants new to botanical science, there were Native Americans who were already well acquainted with many of those species before his arrival. That includes the above mentioned Psorothamnus fremontii and Fremontodendron californicum which were used medicinally and for rope-making fiber, respectively.

A search of the Native American Ethnobotany Database turns up nearly 90 Native American uses for plants bearing Frémont’s name. In these cases, the botanical name fails to account for the Native knowledge of, and relationship with, these plants. This is, unfortunately, not uncommon historically when it comes to the naming of plants.

It is also worth noting Frémont’s troublesome interactions with Native people. Around the time he collected Fremontodendron, Frémont was involved in several skirmishes with Native people, one of which was dubbed the Sacramento River Massacre and described by a participant as “perfect butchery.”

Frémont was hardly alone in his treatment of Native people. The term Manifest Destiny was coined the same year as Frémont’s third expedition. The doctrine held that the expansion of the United States across the continent was inevitable and justifiable. Thousands of Native Americans were killed in California in the decades following Frémont’s expedition. California’s governor apologized for what he called “genocide” in 2019 and pledged to work to change how these atrocities were described in history books.

Despite Frémont’s complicated history, his contribution to the botanical understanding of the American west is undeniable. Take a deeper dive into Frémont’s botanical accomplishments in Stanley Welsh’s book John Charles Frémont, Botanical Explorer. You can also explore more digitized specimens collected by Frémont on

Cassidy Moody — Senior Digital Media Specialist

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