Libraries and Botany: Digital Resources

3 Soulsby

Second edition of Basil Soulsby’s catalog of the works of Linnaeus, Biodiversity Heritage Library

One of the attractive features of the meeting of botanical and horticultural librarians that I attended in New York recently (see the last two posts 1,2) is that it included both Europeans and Americans.  Since Europe is home to so many historical collections of specimens, manuscripts, and botanical art, it was great to learn more about these treasures.  It was even better to discover how many of these resources are now available digitally.  One of the high points of the meeting for me was the presentation by Félix Alonso, head librarian at the Royal Botanic Garden in Madrid.  I already knew that this library has a magnificent collection because many of its treasures are available through the Biodiversity Heritage Library (BHL), and I was glad to hear that the institution is developing a new interface to make it more user-friendly.  Accessibility was Alonso’s major theme, as he outlined plans to move the library from a collection-centered to a service-centered focus, including opening it to children for the first time in its 250-year history.

Yet another group meeting at NYBG along with the European and American librarians, was the Linnaeus Link Project, an international collaboration among libraries with significant holdings dealing with Carl Linnaeus.  It is funded, maintained, and coordinated by the Linnean Society of London, which holds the bulk of Linnaeus’s specimens, manuscripts, and books, bought from his widow by the British botanist James Edward Smith in 1784.  However, a number of institutions also have substantial holdings, and the project aims to make all the Linnaeus material available through a union catalog.  Lynda Brooks and Isabelle Charmantier of the Linnean Society Library presented on Linnaeus Link and that’s how I was introduced to “Soulsby numbers” used to identify each record.  Basil Soulsby produced the second edition of his Catalogue of the Works of Linnaeus in 1933, recording all Linnaean writings and works about Linnaeus published up to 1931; the last entry was number 3874.  Linnaeus Link uses these numbers to identify items in the Union Catalogue and is also assigning post-Soulsby numbers to items not mentioned by Soulsby; there are over 400 of these.  This project gives a glimpse into the world of librarianship and the meticulous processes involved in coordinating materials spread out over several countries.

Isabelle Charmantier also presented on the work being done to digitize the Linnean Society collections, which go well beyond those of Linnaeus and include the herbarium of the society’s founder James Edward Smith, as well as his seed collection that is now being conserved.  The seeds are still enclosed in their original wrappers that include letters, sermons, newspapers—obviously of value in themselves.  There are also the archives of Linnean Society Fellows such as Charles Darwin and Alfred Russel Wallace, and art including the watercolors of Nepalese plants that were done by an Indian artist under the direction of Francis Buchanan Hamilton.  He traveled to Nepal in 1802-1803 and recorded over a thousand species there.  Charmantier noted that at the moment, the Society has data on three platforms with variable metadata and would like to undertake the major task of uniting them, thus making the information available to users through a single search engine.

Another great botanical library is at the Royal Botanic Garden, Kew and the head of the library, Fiona Ainsworth, described its massive holdings: 300,000 books and pamphlets, 200,000 works of art, and 7,000,000 archive sheets.  At the moment, there is no digital catalog for the art collection, and it would be ideal to have it along with the herbarium and economic botany collections cataloged in one system with the library.  That is part of Kew’s plans for the future.  For the present, it is working on a five-year project to digitize and transcribe over 2000 Joseph Dalton Hooker letters, that are available on the Kew Library website.  This is a tremendous resource, especially when seen in relation to the letters of two great American botanists Asa Gray, whose correspondence has been digitized at Harvard University, and John Torrey, whose letters are now being digitized and transcribed at New York Botanical Garden (NYBG).

Stephen Sinon, NYBG’s archivist and curator of Special Collections, described the ongoing Torrey Transcription Project.  The noted 19th-century botanist John Torrey spent his life in New York and taught at both Columbia and Princeton.  He gave his letters and herbarium to Columbia College (now Columbia University), but these were transferred to NYBG when it was founded in 1898.  Most of the Torrey letters are incoming correspondence.  Almost ten thousand pages have been digitized and over 2,500 transcribed by volunteers through a crowdsourcing website.  This massive undertaking is being funded by NEH and the Carnegie Foundation of New York.  The resulting digital images are available not only through the NYBG’s Mertz Library website, but on BHL,, and the Digital Public Library of America (DPLA).  Mentioning this project moves me away from my focus on Europe in this post, but it’s a reminder that botany knows no borders and has always been a global enterprise.  Torrey, Gray, and Hooker knew each other, wrote extensively among themselves, and visited each other’s countries.  The Americans and the British were also rivals in describing American plants, with Hooker and his colleague George Bentham avidly courting collectors, particularly in Canada, but they did not spurn US collections as well.  Torrey and Gray were well aware of this; the letters between them have many mentions of needing to name American plants quickly to prevent the British from doing it first.

Torrey and the Plant Collectors

Virtual Herbarium Image - LAPI Scan

Frasera parryi Torr., type specimen at NYBG; collected by C. Parry in California in 1850

At the end of the last post, I mentioned John Torrey’s efforts to obtain more specimens of the plant that would become Darlingtonia californica when he published a description in 1853. It was the only plant from the Wilkes Expedition that merited it’s own publication, and the California botanist Alice Eastwood (1945) deemed it the most remarkable plant that Brackenridge had collected. But it was only one of hundreds that Torrey dealt with over the years. In his letters from this time, he mentions several other collectors he was corresponding with and trying to get placed in exploring parties so they could travel to areas where little collection had been done previously. He was somewhat like a general attempting to position his troops most advantageously and also to use their spoils to the greatest advantage. Charles Parry, another former student, was one of his major contacts, and there are a number of letters to Gray where Torrey worries about Parry catching up with a contingent of the US-Mexican Boundary Survey (1848-1852). At one point, Parry writes that he is stranded without transportation, and Torrey moans of his inability to correct the situation. At another point, Torrey writes to Darlington that he will send some 60-70 specimens Parry collected on the survey. He notes that Parry could only make six sets, and Darlington is getting one of them, a reminder of the high regard in which Torrey held the older man.

In earlier letters to William Brackenridge, at the time they were working on the latter’s fern book (1855), Torrey complains of competition from other botanists. While writing up some of Frémont’s plants on September 26, 1848 he notes: “Want to get a dozen descriptions out before they are anticipated by others now collecting in California.” He is naming a new plant after Frémont because the first he named turned out to be already published by Prince Maximilian (of Wied-Neuwied) who had followed up exploration of Brazil with a trip to the Great Plains in 1832. In the same letter, Torrey gives a litany of what various US botanists are working on at the moment: Moses Curtis on fungi, George Engelmann in St. Louis on cacti, Asa Gray on the collector Augustus Fendler’s New Mexico collection and Ferdinand Lindheimer’s Texan plants—both the result of border survey expeditions, Edward Tuckerman on lichens, William Sullivant on Wilkes Expedition mosses, William Oakes on New England plants but he “went overboard in a ferry accident,” and John Carey on mosses. The latter was British but lived in the US for 25 years, spending a good deal of time visiting Gray and Torrey while working on his descriptions of plants including the lamb’s quarters family. This list indicates the breadth of Torrey’s correspondence, and while he often complained of the stresses of his jobs at Princeton and Columbia, he still managed to work with his plants and write to those in the field.

This juggling came to an end when Torrey was given the job of assayer at the US Mint in New York in 1855, a position he held until his death in 1873. While it meant a decent salary and a more settled life that didn’t involve commuting to Princeton, it also meant that he was returning to his earlier field of chemistry and moving away from botany. Still, he managed to continue some work with Gray, but the excitement of the 1840s and early 1850s was gone. The Civil War exacerbated the situation. As Jeremy Vetter (2016) notes in his recent book on the post-Civil War natural history surveys, the military expeditions of the pre-war era were over. However, Torrey did have two opportunities to finally visit the West in the years before his death. He went on assayer business but was able to finally get into the field to do a little botanizing and to see some of the plants that he had named as well as his namesake, Torreya taxifolia.

I have enjoyed learning a bit about Torrey and also about the American history and the botanical history in which he participated. Today when social network theory is often used to describe the relationships among scientists and science ideas, Torrey would make a good case study for how botany in the 19th century moved forward. At this point I would also like to mention a more recent American botanist, James Reveal, who wrote a long article (2014) on Torrey’s life and work shortly before his death in 2015. It is a monument to both of them. Reveal was noted not only for his work in systematics and nomenclature but also for his extensive contributions to the history of American botany, including the classic Gentle Conquest (1992). When I was beginning my forays into botany I discovered his extensive web presence with a website on the botany of the Lewis and Clark expedition, which was the beginning of my explorations of botany and American history.


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

Eastwood, A. (1945). An account and list of plants in the Brackenridge journal. California Historical Society Quarterly, 24(4), 337–342.

Reveal, J. L. (1992). Gentle Conquest: The Botanical Discovery of North America with Illustrations from the Library of Congress. Washington, DC: Starwood.

Reveal, J. L. (2014). John Torrey: A botanical biography. Phytoneuron, 100, 1–64.

Torrey, J. (1853). On the Darlingtonia californica: A new pitcher-plant from northern California. Washington: Smithsonian Institution.

Vetter, J. (2016). Field Life: Science in the American West during the Railroad Era. Pittsburgh, PA: University of Pittsburgh Press.

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.