Darwin’s Botanists: Asa Gray

Holotype of Abutilon parvulum collected by Charles Wright for Asa Gray, Harvard University Herbaria.

This last post in the series (1,2,3) on Charles Darwin and the botanists who supported his work deals with an American, Asa Gray (1810-1888).  He received his medical degree at Yale University, but like Joseph Dalton Hooker (see last post), had little interest in practicing and a great desire to learn more about plants.  He taught at Utica College in central New York State for a short time, while collecting in the area and creating exsiccatae of grasses and sedges (Gray, 1834).  He was eventually drawn to work with John Torrey, a botanist who was teaching botany part time at Columbia College in New York City while also teaching chemistry at Princeton University.  Torrey was impressed with Gray’s herbarium and paid for him to collect in New York and New Jersey.  After this, Gray moved in with Torrey’s family and organized his herbarium.  This gave Gray an opportunity to see many more species than he had encountered up to this time.  He remained with the Torreys for two years until he was offered a position as professor of botany at the newly formed University of Michigan.

In preparing for this post, Gray traveled to Europe to purchase books and equipment, and also to consult much richer herbaria than those available in the US, even for American species.  Visiting Glasgow, Gray stayed with William Jackson Hooker for three weeks examining his North American plants, including many collected by Thomas Nuttall.  Gray discovered that most of the specimens were from northern areas of North America, with the south and west still relatively unexplored.  John Lindley of the Royal Horticultural Society let him take portions of the specimens said to have been collected by Thomas Walter in the Carolinas in the 1700s, something that would be unheard of today (Dupree, 1959, p. 80).  Having gathered a wealth of information, Gray returned home to find that the University of Michigan was still not ready to have him begin work.  When offered a similar position at Harvard University, with the additional responsibility for its botanical garden, he moved to Cambridge and remained there for the rest of his life. 

Gray continued to work with Torrey on the deluge of specimens coming in from US-sponsored expeditions and surveys, including the Wilkes Expedition’s 50,000 plant specimens.  This necessitated another trip to Europe to consult herbaria in Britain and France with their superior holdings of North American plants.  Torrey and Gray did much to eventually alleviate this problem by creating large collections at their home institutions of Columbia and Harvard, while the Wilkes specimens became the nucleus of the US Herbarium at the Smithsonian Institution.  Like Joseph Dalton Hooker (see last post), Torrey and Gray became “imperial” botanists, in that they attempted to retain control over collectors and discourage them from describing species themselves.  They claimed that those gathering specimens didn’t have the knowledge, reference collections, or literature to do the job. 

In 1843, US Navy Commodore Matthew C. Perry signed a treaty with Japan that began to open the country to trade.  While Perry had not wanted a natural history collector on the expedition, two Americans associated with the mission, one a friend of Gray’s, did make a small plant collection and sent it to Cambridge.  What struck Gray about these plants, as well as some other Japanese species he had encountered, was how similar they were to those of the northeast US.  When he had examined a broad enough selection, he arranged them in a table and found that of 580 Japanese species, fewer were in western North America than in Europe, and far more were in eastern North America than in either of the other areas.  Considering this odd result, he posited that the plants in these two areas had a common ancestry.  Due to fluctuating climates, which remained most similar in eastern North America and Japan, the species were better able to survive in these regions.  This was a significant piece of evidence for evolution and Charles Darwin was very pleased with it.

Gray and Darwin began their correspondence in 1855.  Darwin appreciated Gray’s acceptance of species change, though he was less pleased that Gray held that creation still had a role in life on earth.  Gray presented this view most fully in an article in the Atlantic Monthly in 1861, “Natural Selection Not Inconsistent with Natural Theology.”  While disagreeing with it, Darwin did see it as a way to lure more people into the evolutionary fold and arranged for it to be reprinted in Britain (Dupree, 1959, p. 155).  Like Hooker, Gray also provided Darwin with much botanical information for his post-Origin plant studies.  They both experimented in their gardens, and Gray could provide seeds and cuttings of American plants.  In his own work, Gray was stymied by the amount of administrative work he was required to do at Harvard without adequate assistance.  Until he retired, he was the only professor of botany, and the University had never created an infrastructure for botanical research.  Gray managed to set the stage for this at his retirement by donating his herbarium of 220,000 specimens and his library of over 2,200 books to the University and managing the hiring of a staff to at last create a department of botany.   


Dupree, A. H. (1959). Asa Gray: American Botanist, Friend of Darwin. Cambridge, MA: Harvard University Press.

Gray, A. (1834). North American Gramineae and Cyperaceae (Vols. 1–2). New York, NY: Post.

John Torrey: The Daily Life of a Botanist

Darlingtonia californica, type specimen from NYBG

The bulk of John Torrey’s papers are at the New York Botanical Garden. He had donated them to Columbia University, along with his herbarium, and both collections eventually made their way to NYBG. I consulted these archives when I was investigating the relationship between Torrey and the Pennsylvania botanist William Darlington (1792-1863). Darlington was a physician and also a leading citizen of West Chester in the Brandywine Valley of Pennsylvania. He was an avid botanist, and in 1826 became one of the founding members of the West Chester Cabinet of Natural Sciences, which housed natural history collections including his herbarium. Darlington wrote a flora of Chester County (1837) that was considered a model for such publications, and he corresponded with botanists in the US and in Europe. His letter books reveal how he cultivated correspondents. He would write to an illustrious botanist such as Augustin Pyramus de Candolle of Geneva and offer to send North American plants in exchange for European ones. Some of these requests were ignored or simply answered with polite but noncommittal replies. Others, as with de Candolle, were fruitful, in this case bearing not only 77 specimens but also the honor of having a genus of mimosa named after Darlington (Overlease, 1992). In addition, Darlington received specimens and books from William Jackson Hooker, and they continued to correspond.

Needless to say, I found letters from Darlington in the NYBG Torrey archive, but for Torrey’s end of the communications, I had to turn to the Darlington archives at the New York Historical Society. Not surprisingly, Gray also traded letters with Darlington, and also wrote to Torrey about him. Here a combination of the Torrey archives and those of Gray at Harvard, which are all online, yielded interesting material. And the Smithsonian provided letters from Torrey to Brackenridge. I cannot claim to have investigated these sources extensively. I was interested in a span of a few years in the early 1850s, but in looking for information on how Torrey came to name a California pitcher plant after Darlington: Darlingtonia californica, I also got a sense of Torrey’s passion for botany. Sometimes the letters between Torrey and Gray were very frequent as if they were frustrated at not being able to work at adjacent desks as they had years before.

Often it was Torrey who received the specimens and then sent them on to Gray. On October 24, 1851 Torrey wrote of an “agreeable surprise” he had the night before: a visit at his laboratory from his “old friend” Dr. Gilbert Hulse. This suggests that Torrey used his evening hours to catch up on botany and was pleased when Hulse “on the table laid a little chubby parcel of plants” he had collected in California. Among them were two surprises, one was a good specimen of a plant he had just named after Darlington to replace the early one named by de Candolle which had been synonymized by George Bentham. Unfortunately, Torrey had used a rather meager and damaged specimen for his descriptions, and this better example indicated that the plant was not a new genera, but a styrax. Torrey’s hasty work on this plant, using inferior material, suggests how frantic the “race” was to name American species. The competition was not so much from compatriots but from what Darlington termed the “invidious” Europeans, using the adjective specifically to describe George Bentham, who had renamed the first Darlingtonia.

Offsetting this disappointment were flowering specimens of the California pitcher plant Brackenridge had collected in 1841, but without a flower. Torrey had been anxious to describe the plant because the pitcher has a unique form: hooded, with two leaf-like appendages hanging from the hood’s edge. However, without a flower, publication wasn’t possible; the only thing close to flower material was the flower stalk. Torrey had complained to Brackenridge about the overall quality of the material collected in California. The latter resented this, writing that Torrey had no idea how difficult it was to find, collect, and press plants while dealing with poor supplies, rough terrain, and bad weather. Torrey, a perfect example of what was termed a “closet botanist” who avoided the field, wrote Gray that he didn’t think much of Brackenridge’s excuses since Frémont had brought back much better plants and “far more numerous specimens.” Charles Pickering, also on the Wilkes Expedition, came in for even greater scorn: he “seemed to look for the most starved and ill-looking specimens and then took merely one of each kind.” Not collecting multiples left Torrey without specimens to distribute to other botanists, a particular problem in cases where he needed help in identifying the plant.

Now, ten years after the original collection, there were, thanks to Hulse’s pitcher plant flowers to be examined, and Torrey set about the task immediately. He also sent a specimen to Gray asking him to pass it on to the artist Isaac Sprague to prepare an illustration. By October 30 he had already had a letter from Gray complaining that the specimen was damaged in transit. Torrey wrote: “I regretted not having defended the specimen better—but I was in haste, and knew how pleased you would be to see it.” There was only one flower left, and he would send it on to Gray once he had finished studying it. He was already working to obtain more specimens. Hulse had stopped by and Torrey had drawn a rough sketch of the flower. Hulse was going to send it “at once to an intelligent friend of his (Mr. Reading—now a candidate for the office of Governor of California) who has long resided within 15 miles of the locality of the plant and who has many Indian servants.”

This telling passage says a great deal about plant collecting at the time. It was the pastime of many men in all walks of life, including politics. Often these men were wealthy, as the number of Mr. Reading’s servants suggests. That servants would be the ones doing the collecting is not surprising. Indigenous peoples were often involved in plant collecting, though this was not always mentioned by those who took credit for the collections. Torrey’s words also indicate how anxious he was to get more specimens quickly. As it turned out, additional examples of this species weren’t discovered for another ten years. In the next post there will be more on Torrey’s work with this plant and his other botanical endeavors.


Darlington, W. (1837). Flora Cestrica. West Chester, PA: Siegfried.

Overlease, W. R. (1992). A short history of the William Darlington Herbarium with an annotated list of plant collectors represented. Bartonia, 57, 82–94.

John Torrey: Dealing with Expedition Specimens

Virtual Herbarium Image - LAPI Scan

Dalea fremontii Torr. ex A. Gray, type specimen from NYBG; collection by Frémont in Nevada 1844

As I mentioned in my last post, I had of course heard of the Lewis and Clark Expedition and to a lesser extent of the Wilkes Expedition, but these episodes in American history were of limited interest to me. The Frémont expeditions didn’t ring a bell at all—until I got hooked on herbaria and botany. My last real contact with American history was in high school, and though I was married to a historian, he focused on European history and being a true academic, stuck to his field and ignored the US past. Then herbarium fever struck and I read books like Andrea Wulf’s (2011) The Founding Garderners, which made me look at Washington, Jefferson, Adams and Madison in a whole new light. It became important to me to know how Jefferson championed American natural history and made sure that Meriwether Lewis knew how to preserve plant specimens. I even read Lewis and Clark’s account of the expedition (DeVoto, 1953). What impressed me most, besides how grueling the trip turned out to be, was how much they used information from earlier explorers and indigenous people. In other words, they didn’t go into the trip as into the unknown. Some of the information proved inaccurate, and there were definitely many surprises, but they had some knowledge of the territories that lay ahead of them.

This combination of information and ignorance is true of all travel, even today. No matter how much preparation, there is always the unexpected—good and bad. That’s what made Jessie Frémont’s (1878) expedition account so riveting, and that’s what made the plants Frémont sent back to Torrey so interesting: they sometimes resembled what had been found in the East but there were also many surprises. Perhaps because he had visited Europe and seen the level of interest in American plants, Torrey lost no time in describing Frémont’s plants as they began to arrive in New York. In essence this was a botanical form of the doctrine of “Manifest Destiny.” This was the idea of the United States’ right to rule from the East to the West coast and was promoted by Senator Thomas Hart Benton, who not coincidentally was Jessie Benton Frémont’s father and championed his son-in-law’s participation in these expeditions. Of the five expeditions Frémont led during the 1840s and 1850s, the first three were the most botanically significant.

In 1853, Torrey published Plantae Frémontianae. At the same time, he was working on the plants collected by the massive Wilkes Expedition (1838-1842), officially called the United States Exploring Expedition but usually referred to by the name of its leader Charles Wilkes. There were six ships and 346 men in this entourage, including nine scientists and artists responsible for recording the natural history of the areas visited. The fleet traveled to South America, Africa, Antarctica, and into the Pacific, visiting Australia as well as exploring areas of Oregon and California, territory that at the time was not part of the United States. Preparation was extensive and involved much discussion and correspondence about who would make up the scientific contingent. Torrey was a logical choice but he was too involved professionally and personally to leave for an extended time. Gray almost signed on, but then received a job offer from the newly founded University of Michigan. That fell through, but he ended up becoming professor of botany at Harvard University. The botanist position on the expedition was finally filled by William Rich who turned out to be less that adequate to the task. His “assistant,” a Scottish nurseryman from Philadelphia, William Brackenridge, became the primary collector by default. Over all, the expedition sent back about 50,000 plant specimens to Washington, DC. There were also seeds and cuttings which Brackenridge was put in charge of nurturing in what would be the beginnings of the US Botanic Garden (Viola & Margolis, 1985).

Torrey was asked by Wilkes to take on identification of the plant material, but he argued that he couldn’t do this without traveling to Europe to access the large herbaria there, as well as the extensive libraries. There just weren’t the collections and books in the US to do the job. Wilkes balked: the US plants had to be identified in the US by American botanists. Eventually, the job went to Gray, with Wilkes relenting and funding a European trip for Gray that allowed him to visit collections in France, Germany, and Britain. This was Gray’s second European foray and rather paradoxically, allowed him to become the dean of American botany. He saw enough plant material from North America to put future collections into perspective. Torrey meanwhile continued his bisected professional life in New York and New Jersey, but definitely kept up on collecting in the West, as his publication on Frémont’s plants indicates. The volume on the Wilkes Expedition’s flowering plants wasn’t published for 20 years, with Gray as the primary author but with many contributions from Torrey and other botanists (Gray et al., 1862). Meanwhile, Brackenridge published on the expedition’s ferns (1855), with a great deal of help from Torrey. Around these publications swirled controversy generated by Wilkes and his committee who were editing the contributions. He did not want a book published in the US to include a foreign language, namely Latin, though this was standard for plant descriptions. Torrey and Gray were appalled, and the ban was finally lifted after much ink was used on the argument, especially because the problem came to a head while Gray was in Europe. It must have been frustrating for Torrey who had to wait so long for letters to find out his friend’s response to the crisis. In the end, though Latin was included, the botanists had to give in on other points to keep publication costs in check. I got a taste of this contretemps while I was investigating some of the Gray-Torrey correspondence, a topic I’ll take up in the next post.


Brackenridge, W. D. (1855). Cryptogamia, Filices, including Lycopodiaceae and Hydropterides,. Philadelphia: C. Sherman.

DeVoto, B. (Ed.). (1953). The Journals of Lewis and Clark. Boston, MA: Houghton Mifflin.

Frémont, J. B. (1878). A Year of American Travel. New York: Harper & Bros.

Gray, A., Tuckerman, E., Bailey, J. W., Harvey, W. H., Curtis, M. A., Berkeley, M. J., & Torrey, J. (1862). Botany.Lower Cryptogamia. II. Phanerogamia of the Pacific Coast of North America. Philadelphia: C. Sherman.

Torrey, J., & Frémont, J. C. (1853). Plantae Frémontianae, or Descriptions of Plants Collected by Col. J.C. Frémont in California. Washington: Smithsonian Institution.

Viola, H. J., & Margolis, C. (Eds.). (1985). Magnificent Voyagers: The U.S. Exploring Expedition, 1838-1842. Washington, DC: Smithsonian Institution Press.

Wulf, A. (2011). Founding Gardeners: The Revolutionary Generation, Nature, and the Shaping of the American Nation. New York, NY: Knopf.

John Torrey and Plants of the West

John Torrey, 1869 By W. Kurtz. Photo in NYBG Torrey Archive [CC BY-SA 4.0 via Wikimedia Commons]

Since I became interested in herbaria several years ago, I’ve discovered a great deal about botany—and about American history as well. My level of ignorance on both was so profound that I had no idea of the close relationship between the identification of the North American flora and the expeditions to discover what lay beyond the East Coast of the United States. I am referring here specifically to 19th-century government-sponsored expeditions. Yes, there were earlier explorations often conducted by colonists like John Bartram or European visitors such as Mark Catesby. But those are topics for another day, as is the great Lewis and Clark Expedition that started a trend which continued for many decades. I am ignoring these worthy subjects in order to home in on the work of a fellow New Yorker, John Torrey (1796-1873). He may not be considered the greatest American botanist of the 19th century—that honor going to Asa Gray—but he definitely would be a close second, in part because he introduced Gray to the world of plant taxonomy.

Torrey himself had his interest in plants nourished by another New York botanist, Amos Eaton, who developed the first botanical teaching laboratory in the US. Torrey received a medical degree from the College of Physicians and Surgeons in New York and practiced medicine for a few years. However, his passion from an early age was for natural history.  At the start of his career a great deal of his energies were given to the Lyceum of Natural History of New York, of which he was a founding member and one of the first curators. In 1819 he published a catalogue of plants growing in and around New York City in preparation for which he kept a Caand A Compendium of the Flora of the Northern and Middle States seven years later. At the same time, he was working with his former student, Edwin James in describing the plants, 481 in all, that James had brought back from the Long Expedition to the Rocky Mountains. This was the type of work that Torrey conducted for many years: not collecting plants himself, but rather studying the collections of others. In 1822, Torrey obtained a position teaching chemistry at the US Military Academy at West Point while he continued his botanical work. He collaborated with Lewis von Schweinitz of North Carolina on sedges as well as mosses. By 1831, Torrey was Professor of Chemistry and Botany at his alma mater in NYC; he also spent several months a year teaching chemistry at Princeton in New Jersey. Neither position was full time, so he needed both to support the growing family he had since marrying Eliza Robinson in 1824. It was in 1833 that he enlisted the assistance of Asa Gray, who had a medical degree but was much more interested in botany than in being a physician.

Gray worked to collect plants and to organize Torrey’s herbarium, while Torrey sailed to Europe, one of his few extensive trips. He wanted to buy a good microscope, and there he could try out a greater variety of models and also inspect the extensive European collections of North American plants. At that time, there was nothing in the US to compare with them. In Paris, he studied André Michaux’s American collections on which the latter based his flora of North America (1803). Torrey also traveled to Britain where he obtained specimens, including some collected by the Scottish botanist David Douglas in Oregon, and talked with William Jackson Hooker (1840) who was publishing a flora of the British territories in North America. Torrey met many of British botany’s luminaries including John Lindley, Robert Brown, and George Bentham, who was working on North American plants as well and being supplied by a number of collectors. This situation was a sore point with Torrey because it meant that many American plants were not described in the US at a time when the country was trying to make a name for itself in many areas, including science.

When Torrey returned home, he continued working with Gray, who by 1834 had moved into the Torrey home. They developed the idea of producing A Flora of North America, several volumes of which were published (Torrey & Gray, 1838-1843), though the project was never finished in part because the task grew significantly thanks to their descriptions of so many new species. When word of their project reached plant collectors and botanists in other states, they were sent many specimens especially since Torrey had done an excellent job of describing the plants James had collected. These contributions came from the likes of Constantine Rafinesque, a noted but eccentric collector, and Charles Short, an avid Kentucky botanist. By this time, plants from several expeditions were also being sent East; five of these were headed by John Frémont who was himself an enthusiastic plant collector. He was accompanied on his expeditions by his wife Jessie, who wrote engaging chronicles of their journeys that were later published (1878) and added to Frémont’s reputation. In the next post, I will describe Torrey’s work on Frémont’s specimens and those of the Wilkes Expedition.


Dupree, A. H. (1959). Asa Gray: American Botanist, Friend of Darwin. Cambridge, MA: Harvard University Press.

Frémont, J. B. (1878). A Year of American Travel. New York: Harper & Bros.

Hooker, W. J. (1840). Flora Boreali-Americana, or the Botany of the Northern Parts of British America. London: H.G. Bohn.

Michaux, A. (1985). Flora boreali-Americana. Paris et Strasbourg, France: Levrault.

Torrey, J. (1819). A Catalogue of Plants, Growing Spontaneously within Thirty Miles of the City of New York. Albany, NY: Lyceum of Natural History of New York.

Torrey, J. (1826). A Compendium of the Flora of the Northern and Middle States. New York, NY: Collins.

Torrey, J., & Gray, A. (1838-1843). A Flora of North America. New York, NY: Wiley and Putnam.