Schildbach Xylotheque at the Ottoneum in Kassel, Germany; photo by DG Fontanills

In the last post I discussed xylaria, collections of wood specimens. Now I want to look at the similar xylotheque. In some cases, the two are synonymous. Xylotheque is a French word meaning wood library, related to bibliotheque, the term for a library of books. Many European xylaria are called xylotheques, but in the 18th and 19th centuries especially in Germany, a number of wood collections were created that were more than just figuratively wood libraries. A wood specimen was cut in the form of a book, and the spine was labeled with the species name. Some of these still exist, such as that of the merchant and illustrator Johann Bellermann whose collection is now at the Austrian National Library (Lack, 2001). In this case, the samples were cut so the books’ “spines” displayed the species’ bark.

Other xylotheques are more elaborate, with the center of the “book” hollowed out and filled with a tree branch as well as flowers and fruit, nuts, or cones. One of the most spectacular is at the Naturkund Museum in Kassel, Germany constructed between 1771 and 1799 by Karl Schlindbach. It’s composed of 530 “volumes;” each has what amounts to a small diorama inside, with wax fruit and leaves still retaining their color. These have bark spines as well as information about the species on the reverse side. They are now kept in special cases (see photo above) with the entire display designed by the American artist Mark Dion who is known for his work with natural history collections. He also crafted several new “books” for the collection. Germany’s forests have long been considered treasures, and so it’s not surprising that such xylotheques would be created there and in other countries of central Europe. Bess Lovejoy has a blog post on two sets found in the libraries of religious foundations, abbeys in the Czech Republic and Austria. These are seen more as historical rather than botanical objects, but there is a xylotheque at the Technical University of Munich that has a historical and a working collections, both are housed in bookcases with glass doors so the term xylotheque is particularly fitting for this institution.

What William L. Stern (1976) referred to as the aesthetic lure of wood is obviously how the foremost attraction of many historical xylotheques. One of the most spectacular was created in the 1870s in Japan by Chikusai Kato, the first illustrator at the Tokyo botanical garden. It consists of boards of different woods, each framed with the corresponding bark and decorated with paintings of the tree’s leaves, flowers and fruit. The largest collection of these, 155 of them, is at the museum of the Berlin Dahlem Botanic Garden (Nagata et al., 2013). They are housed in specially designed wooden cupboards from the late 19th century. There are also 26 specimens at the Royal Botanic Garden, Kew, where they were recently on display as part of an exhibition of Japanese botanical art. In preparation for the exhibit, these artifacts were restored, so they are now particularly beautiful examples of an unusual cross between specimen and botanical illustration. One of these is made of ginkgo wood and depicts its distinctive leaves. Kew borrowed a watercolor of the gingko, also by Kato, so they could be hung together. Perhaps less spectacular but nonetheless noteworthy is the Peiffer Xylarium at Delaware State University. Each of the wood specimens has a laser cut image of the tree’s branch, leaves, flower, and seeds and/or fruit; also engraved on each block are the common and Latin names. These were done by artist Barbara Newlon. Delaware State has a very active herbarium, and this collection is a wonderful adjunct to it, with many specimens contributed by Prof. Randel Peiffer.

Before leaving the topic of xylotheques, examples of a combination of wood and text, I should mention that there are many books containing images of wood specimens, and sometimes even wood specimens themselves. The Austrian National Library has a copy of Flora rossica (1784-1789) by Peter Pallas, a German explorer who studied the economic conditions of the regions he visited, and in this case produced a collection of woods found in Russia, an area that had been little investigated earlier. This is a reminder that a great deal of the impetus for the study of woods in the past and the present is economic. It is easy for those living in urban areas to forget this, but as someone who now travels regularly through the Carolinas, I am often reminded of the importance of logging in these areas.

With the development of photography, it became much easier to document wood grain. Manuel Soler is a Spanish wood collector who has published four books of pictures of wood specimens he has collected over the years. He now has over 4000 samples which he displays in a small hut he built for the purpose. He is one of a number of private collectors whom I’ll mention in a future post. But before I sign off, I’d like to cite The Woodbook (Leistikow, 2014) that includes photographs of all the woods presented in Romeyn Hough’s American Woods, first published in 14 volumes between 1888 and 1928. The original contains specimens of each species mounted on stiff paper—presenting three cross-section cuts of each wood to illustrate all characteristics of the grain: radial, horizontal, and tangential. Also included in The Woodbook are updated descriptions of the trees as well as lithographs by Charles Sprague Sargent of the leaves and fruit of most trees. This is a beautiful book, but it only hints at the magnificence of the original series.


Hough, R. B. (1888). American Woods. Lowville, NY: R.B. Hough.

Lack, H. W. (2001). Garden Eden: Masterpieces of Botanical Illustration. Cologne, Germany: Taschen.

Leistikow, K. U. (2014). The Woodbook. Cologne, Germany: Taschen.

Nagata, T., DuVal, A., Lack, H. W., Loudon, G., Nesbitt, M., Schmuli, M., & Crane, P. (2013). An Unusual Xylotheque with Plant Illustrations from Early Meiji Japan. Economic Botany, 67(2), 87–97.

Stern, W. L. (1976). Multiple uses of institutional wood collections. Curator, 19, 165–170.

Xylaria: Preserving Wood

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Augustine Henry specimen box at the National Botanic Gardens of Ireland, photo by MCF

Among the herbaria I’ve visited, one of my favorites is in the National Botanic Gardens of Ireland at Glasnevin in the Dublin suburbs. There’s obviously some chauvinism here, because my mother visited the gardens as a high school student. Incidentally, she was a winner of the All Ireland Prize in Botany, and to prove it, my family has a massive document with Gaelic on one side and English on the other. But my love of the herbarium is based more on several jewels it houses, including specimens collected by Augustine Henry (1857-1930), a legendary plant hunter who had a long career as a physician with the Imperial Maritime Customs Service in China. His job seems to have been an excuse to get him to places where he could explore exotic flora, and he sent back 150,000 specimens to Kew, with some duplicates ending up at Glasnevin. His specimens included 25 new plant genera and over 500 new species. Henry is also known for giving the plant collector Edward Wilson directions on where to find Davidia involucrata, the handkerchief tree, which had been originally discovered by a French missionary, Armand David; in the Irish National Herbarium there is a specimen of Davidia that Henry himself collected.

But this was hardly Henry’s only connection with trees. After returning from China, he collaborated with Henry Elwes in collecting material for and then writing the seven-volume The Trees of Britain and Ireland (1906-1913). Elwes was a wealthy landowner with a passion for botany, and for trees in particular. To prepare this massive work the two traveled all over the British Isles in Elwes’s automobile, a daring feat at the time. They took photos, collected specimens, and then had illustrations made from these materials. The specimens are now at Glasnevin as the Augustine Henry Forestry Herbarium having been curated and then donated by his widow, Alice . After Henry died, she organized the 10,000 specimens collected for the project and chose to store the bulkier items like cones in the type of boxes used in clothing stores at that time. This was an ingenious solution to storage in the days before the manufacture of boxes specifically for herbarium specimens and before plastic bags were invented. The boxes, and the specimens, have held up very well. Each box is beautifully labeled as to its contents, and each has a cord around it so that it can be easily removed from the shelf. It is a thing of beauty to see rows of these lined up in compact shelving (see photo above). Another thing of beauty is the climate-controlled room where the treasures of the Glasnevin botanical library are stored. Here is more Henry material, including his heavily annotated copy of Trees; it shows how rigorously he corrected errors and added new information, including clippings of journal and newspaper articles.

Though I chose to begin a series of posts on xylaria with Henry’s material, technically these are not part of Glasnevin’s xylarium of about 1000 specimens. For the uninitiated, a xylarium is a collection of wood specimens, usually relatively small blocks of wood, that are used in identification of unknown wood samples as well as in other research. The Royal Botanic Gardens, Kew maintains an Index Xylariorum, sort of an Index Herbariorum for wood collections. The former is now in its fourth edition. There are about a million wood specimens in such collections worldwide with the largest at the USDA Forest Products Laboratory in Madison, Wisconsin with about 105,000 specimens including collections that were originally at the Yale School of Forestry and the Field Museum in Chicago. Another major xylarium, at Duke University, was sent to the du Pont Winterthur Museum.

These shifts were made in the mid-20th century and suggest that some institutions became less interested in wood collections than in the past. William L. Stern decried this trend as far back as 1973, and in 1976 described the history of the largest xylaria in the United States, including those I’ve just mentioned along with the ones at the Smithsonian, Harvard University, and SUNY College of Environmental Science and Forestry. Most of these collections were begun in the early 20th century, and they include microscope slides of thin sections of wood used in the study of wood anatomy. This was an area of focus in many xylaria for several decades, but then interest faded. This is one reason for the amalgamation of collections, along with the fact that wood specimens take up a great deal of room and like all other natural history collections, require active curation. One xylarium that has remained active from the 19th century on is at Kew. At one time, two of the four economic botany exhibits there dealt with wood and the xylarium remains a lively place.

Xylaria serve a number of purposes including studies in wood anatomy that I’ve already mentioned, and most prominently the identification of unknown woods, which can be everything from someone’s dining room table to objects from illegal trade in rare woods. Because of the economic significance of the wood industry, many governments especially in developing countries have set up xylaria over the past few decades, so while their use seems to be declining in the developed world, the number of xylaria overall is increasing. Forensic specialists also consult xylaria for criminal investigations, and archaeologists use them to identify the species found in wooden objects or structures. Wood specimens are particularly helpful in identification when they are vouchered, that is, when the specimen is linked to an herbarium specimen derived from the same tree; this makes identification much more trustworthy. Index Xylarium notes the percentage of vouchered specimens in each collection, and it varies from zero to almost 100%.

Stern makes two interesting and seemingly contrary points about the process of wood identification. He sees it as less pleasurable than identifying a plant from an herbarium specimen: “A wood specimen, at best, is only a fragment of an organism” (1973, p. 79). He finds the process nothing more than a necessary part of working in a xylarium and much prefers wood microanatomy, which involves an even smaller fragment, but includes the pleasure of microscopic examination. However, in another article (1976) he ends with an admission that one of the reasons for studying wood is aesthetic: so many woods are simply beautiful to look at. This aspect of wood collections should become clear in my next post on xylotheques.

Note: I am grateful to Dr. Matthew Jebb, Director of the Irish National Botanic Gardens, Glasnevin, for showing me its herbarium and library, and introducing me to the Augustine Henry material held there.


Elwes, H. J., & Henry, A. H. (1906-1913). The Trees of Great Britain and Ireland (Vol. 1–7). Edinburgh, UK: Elwes & Henry.

Stern, W. L. (1973). The wood collection–what should be its future. Arnoldia, 33, 67–80.

Stern, W. L. (1976). Multiple uses of institutional wood collections. Curator, 19, 165–170.

Torrey and the Plant Collectors

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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

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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.

The Algal World: So Much More


Fucus evanescens specimen from the US National Herbarium, Smithsonian Institution

I have devoted the last two posts to diatoms and before that to the 19th-century interest in seaweeds in general. But there are many other aspects of algae deserving attention, for example, the onslaught of forces causing damage to ocean ecosystems and thus to algae including a documented decrease in phytoplankton over the last century. At the same time, excessive algal blooms have become more common such as several on Lake Erie, including one that covered an area the size of New York City. Also, a number of macroalgae collected in the 19th century have not been found again in the 20th. In order to have reference specimens readily available to monitor aquatic life, the National Science Foundation has funded a major project called the Macroalgal Herbarium Consortium. Forty-nine US institutions have digitized their macroalgae collections, and all these specimens are now available through one website, the Macroalgal Herbarium Portal. Kathy Ann Miller, a curator of algae at the herbarium of the University of California, Berkeley explains the importance of the collection she manages in a short video. She makes the point that this is a living collection in the sense that she and her students frequently go on collecting trips along the California coast, sometimes finding as many as 400 species in an area. At the moment the Berkeley collection includes more than half of all known macroalgae species.

The Steere Herbarium at New York Botanical Garden also has an impressive collection, and now thanks to the Macroalgal Portal we are all able to access these specimens on the web. This doesn’t do us any good if we don’t know much about algae. But the web can help with this problem. The Smithsonian, also with a significant macroalgal collection, hosts a website on seaweed research with links to other sites, many dealing with species in other parts of the world. If you want to look at some beautiful specimens, and get basic information on them, the natural history museum in Wales also has a good site. The Natural History Museum’s AlgaeVision portal combines basic information on algae with links to its online collection. So once you’ve read about algae, you can investigate many of the different types, and if you just want to feast your eyes on some beautiful specimens you can’t do better than to go to Seaweed Collections Online. I hope that by this time, I have whetted your appetite for these water-loving plants, of all sizes, from the unicellular to giant kelp. Next time you are near a body of water, particularly at low tide at a beach, seek out some specimens. They may not look very attractive and are likely to be slimy to the touch, but persist and maybe stick a few in a plastic bag. When you get home, put them in water, slip a piece of heavy white paper under one of them, and slowly lift it out of the water, keeping it horizontal. See what you’ve got. Your specimen might look surprisingly good. If so, cover it with wax paper, place it between two pieces of board or cardboard and let it dry. Needless to say, if you need help with all this, it’s easy to find on the web. Perhaps you will be in the vanguard of a new era of interest in these organisms.

The Algal World: More Diatoms


Round Loch of Glenhead, watercolor by Martyn Kelly.

I have a bit more to add on diatoms; there just wasn’t enough space in my last post. I have already mentioned diatomaceous earth, composed of the remains of ancient diatoms. It is used for polishing because of the abrasiveness of the glassy shells made primarily of silica. The tiny, hollow shells have a great deal of surface area making them effective filtering agents as well. The earth can also be employed as an insecticide because the abrasiveness damages the waxy covering on many insects. Perhaps the greatest impact of diatoms on our life style today is that their internal remains are a major component of fuel oil, which was created from deposits of many kinds of plant material including the aquatic variety. In fact, the diatom contribution was so significant that some researchers today are considering diatoms as a form of future biofuel, in part because, among phytoplankton, a higher proportion of their fatty acids are monounsaturated making them a better starting material for biofuel.

One of the best and most engaging ways to learn more about diatoms and about how they are used to evaluate aquatic environments is to read the posts on Martyn Kelly’s Of Microscopes and Monsters blog. Kelly heads a consultancy firm in Britain that specializes in studying freshwater ecosystems, and diatoms are key to this research. He is an expert in the field but he writes very appealingly for nonspecialists. He has even produced a book on the subject that is available for a free download from his website. He describes what a diatom population tells about water quality, and how this changes with season and location. Kelly has been doing this work long enough that he can also discuss how things have changed—for better or worse—over time. He travels widely on business so there are posts on his experiences studying diatoms and other phytoplankton in many locations; there have been recent posts from India.

I should note that Kelly can definitely be opinionated in his posts, which is not a bad thing. He provides a sense of the political and economic issues surrounding diatoms—they are not only about beauty. As an independent consultant, he is a little freer to speak his mind, and as a Briton facing exit from the European Union, he has some interesting things to say that what this might or might not mean for environmental regulations in the United Kingdom. Kelly also looks at the local level, at such issues as how a new housing development is likely to affect nearby lakes and streams and what can be done to mitigate the changes. So there are many reasons why his writing is worth checking out.

What makes Kelly’s website particularly interesting is that he is also an artist, who returned to school to take up art seriously. I don’t think it’s a coincidence that he chose to focus on diatoms, because as I said in my first post on algae, they are particularly appealing aesthetically, and this is especially true of diatoms. In his effort to communicate about aquatic environments, Kelly sometimes includes his watercolors in posts. They are beautiful and portray the atmosphere of an underwater world. He includes not only diatoms but other planktonic organisms that would be associated with them in a particular body of water. Some of these works are also included in his book. I think it’s particularly powerful when a biologist is also an artist, because they bring knowledge and years of observation to their art. Kelly presents diatoms in a very different way than does Haeckel, whose portrayals are greatly enlarged, with all the structural details laid out for the viewer as static, structural monuments. Kelly’s diatoms, on the other hand, do not have as many details, but they are shown as immersed in their environment rather than separate from it, and there is a sense of movement. I see these two approaches as complementary and definitely worth studying. We are very fortunate that both are freely available on the web.

Kelly has written on other algal art available on the web, including Andrew McKeown’s cast-iron sculptures of diatoms at East Shore Village on the Durham coast in Britain. They are in a park with a view of the ocean and are tangible expressions of these tiny creatures, something a child could play on and experience in a very different way than they could the real thing. At the other end of the size spectrum, there is a genre, if you can call it that, of arranging diatoms into patterns on microscope slides, a form of tiny art. This has been going on since the 19th century, but still persists today. One major exponent was Carl Strüwe, a German photographer with an expertise in photomicroscopy. He created stunning images, many of diatoms artfully arranged; there was an exhibit of his work held last year called Microcosmos. He was not alone; there was a small group of devotees of this art in the Victorian era, mirroring the broad interest in both microscopy and aquatic organisms. Nor is the practice dead. Klaus Kemp is a British microscopist who creates complex symmetrical arrangements of diatoms. There is a fascinating video of his work and how he creates them. Some people might consider this scientific kitsch, but I see is as one more way to lure nonscientists into the world of science through wonder. They may be initially attracted by the symmetry, become more interested when they learn that the pattern is created under a microscope, and are then hooked by the intricacy and beauty of each tiny element: how can creatures so small be so complex?

The Algal World: Diatoms


Diatom plate from Haeckel’s Art Forms in Nature

I was first attracted to diatoms by their exquisite beauty. When I studied aesthetics many years ago, beauty was often defined in terms of categories such as symmetry and form, and diatoms are definitely exemplars of both. They are one-celled algae, each encased in a glassy silica shell that varies with species. These structures can be elongated, triangular, circular, square, or more elaborately shaped. There is no better introduction to them than the diatom plate [shown above] from Ernst Haeckel’s Art Forms in Nature (1904). There are also great microscope photographs of diatoms on the web, at sites such as Micropolitan University. If you want more than just images, the Natural History Museum, London has Diatoms Online and the Academy of Natural Sciences (ANS) in Philadelphia (now part of Drexel University) has a Diatom Herbarium, both a real and a virtual space.

I visited the diatom collection at ANS two years ago and was drawn into a very different kind of herbarium world. Yes, there are metal cabinets, but they are filled with boxes of microscope slides, not sheets of white paper in folders. This collection was begun in the mid-19th century by members of the ANS who were interested in microscopy. At the time, this was, like seaweed, a hobby for many people who had the money to have leisure time and to buy a microscope. Some were physicians who had some familiarity with microscopes through their profession; others included bankers and industrialists who simply became fascinated with what couldn’t be seen with the naked eye. Like seaweed collecting, this was an area of interest in Britain, and also on the Continent, and had begun in the 17th century (Stafford, 1996). By the mid-19th century, microscope optics had improved and the instruments were easier to use. Many of the ANS microscopists were interested in fossilized diatoms found in diatomaceous earth, which could be found in areas around Philadelphia. This fine, sandy material is used in polishing among other things and represents the remains of organisms that lived in great numbers millions of years ago. Since diatoms are responsible for 20-25% of the earth’s carbon fixation, it’s difficult to overestimate their abundance, both now and in the past.

Eventually, the microscopists’ diatom collections morphed into the ANS Diatom Herbarium, which now houses the second largest such assemblage in the world. Along with slides, there are small glass bottles filled with diatomaceous earth collected in various locations. These are particularly difficult to catalog because each sample contains many species. In some cases, small portions of these sands have been separated out with individual species mounted on slides, but as Maria Popanova, the curator of the collection, notes the bottle that was the source of a particular mount wasn’t always recorded on the slide. There are ways of backtracking using dates and collection sites, but it’s time-consuming work and slows down digitization of the collection. However, 63,000 specimens are now available online. Also at ANS are rare 19th-century exsiccatae that contain many type specimens. These are store in book-like boxes with specimens either mounted on slides or in tiny envelopes. A counterpoint to these historically important items are posters on the walls of scanning electron microscope images of diatoms revealing an even more elaborate detail than that provided by a light microscope. The images are more expensive to produce so not every diatom receives this attention, but these images highlight the complexity of these minute structures.

I could easily dwell on the aesthetic aspects of these creatures, but I want to also stress their scientific significance. There are good reasons why the herbaria such as the ANS and NHS, among many others, maintain diatom collections. The cells can tell us a great deal about aquatic life of the past, the present, and the future. Diatoms serve as useful markers of aquatic ecosystem health. Their shells remain after death, providing stable evidence of water quality. A water sample’s use in monitoring usually deteriorates with time as organisms die, but this is a lesser problem with diatoms. Also, they are ubiquitous, found all over the world in both fresh and salt water. The species present at a site depend upon the presence or absence of pollution, among other factors.

Part of the research done at ANS involves water monitoring studies and having a rich diatom collection, including many type specimens, as reference adds weight to the findings. This work has a long history at the ANS, and the person most responsible for building its stature was Ruth Patrick (1907-2013). She had a doctorate based on diatom research from the University of Virginia and wanted to volunteer at the ANS in the 1930s. She was kept out for several years because they didn’t accept women. She finally became a volunteer in 1935, serving first as a virtual servant to the Microscopy Section, setting out specimens for their meetings among other duties. She eventually became the first woman member of the ANS. In the late 1940s, after she became a paid employee, Patrick founded the ANS Limnology Department. Through her work, the ANS developed a focus on freshwater diatoms; before that it had collected mostly fossils and saltwater species. She directed studies on rivers and streams, especially in terms of using diatoms to gauge water quality, and her influence lives on in the ANS’s Patrick Center for Environmental Research.


Haeckel, E. (1904). Art Forms in Nature (Vol. 1974 ed.). New York: Dover.

Stafford, B. M. (1996). Artful Science: Enlightenment Entertainment and the Eclipse of Visual Education. Cambridge, MA: The MIT Press.

The Algal World


Anna Atkins, Confervae, Cyanotype. Digital image courtesy of the Getty’s Open Content Program.

A recent Twitter post from the Manchester Museum Herbarium said that they were getting ready for a tour; attached was a photo of a seaweed album and specimen. This reminded me that I was lured into the herbarium world by just such material. I was on a tour given by the curator of collections, Marilyn Massaro, at the Roger William Natural History Museum in Providence, Rhode Island. The museum has a 6,000-specimen herbarium, most dating from the late 19th and early 20th centuries; it is like a botanical time capsule of the period. Rhode Island has so much coastline, it’s not surprising the collection includes seaweed albums, since creating them was a popular pastime in the 19th century, especially among women. It was considered ladylike to collect plants, and many macroalgae are so aesthetically pleasing that they were particularly attractive specimens. Blank albums were even sold for collections created on vacation. When Dr. Massaro showed us several of these books, I was fascinated by them. When I returned home, I tried to learn more about herbaria, and this became a long-term obsession with them, which, in turn, led to this blog.

I returned to Providence several months later for a better look at the collection, and Dr. Massaro showed me related archival material. This included a 1926 letter from William L. Bryant, the museum director at the time, to Mrs. George P. Wetmore of Newport thanking her for the collection of sea mosses she had donated. This is one in a series of letters among Bryant, Mrs. Wetmore, and her daughter, Edith Wetmore. When Edith sent the album, she asked Bryant to thank her mother. He wrote back asking for her mother’s name so he could thank her properly. Edith responded in another handwritten note saying: “It did not dawn on me that you would not know that, coming as the album did from Newport, you could only have received it from Mrs. George Peabody Wetmore.” George Peabody Wetmore was governor of Rhode Island from 1885-1887, and Edith obviously assumed that his name would still be familiar to all 40 years later. As a final point, Edith mentioned that this collection was originally offered to the Children’s Museum in Newport, but they already had such an album and thought it should go to a “bigger institution.” This suggests two things: that they knew the Wetmore name, and that such albums were common at the time. I now appreciate the latter fact because most herbaria in coastal areas in the US and Britain boast these collections. They are hardly a rarity, even though preparing specimens required a certain skill. Some are now considered more as works of art.

Unlike terrestrial plants, seaweeds don’t have much rigid structural material, so they are limp once removed from water. The trick to mounting them is to slip a sheet of stiff paper under a specimen floating in water and then raise the sheet with the plant spread upon it. There is enough sticky material on the plant’s surface that it doesn’t have to be pasted down. It will adhere to the paper, and voila, there is a herbarium specimen—or an album page. With a little practice, this technique works remarkably well and results in beautiful specimens, with all the delicate filigree of the algae artistically arranged. It is no wonder that seaweed albums became such a fad.

But interest in macroalgae was really more than a fad, it was a serious area of study for many professional and amateur botanists. The leader of the pack was probably William Henry Harvey (1811-1866), an Irish botanist who wrote extensively on algae, producing definitive works on British, North American, and Australian species. While in Australia he collected numerous specimens of each species in order to finance his trip, writing that he intended to create 50 collections, with 200 to 600 specimens in each. From the number of Harvey specimens in the US, Britain, and Australia, he must have come close to reaching his goal. Even the small William Darlington Herbarium at West Chester College in Pennsylvania has 272 sheets, and Darlington wrote to John Torrey that he had heard about Harvey’s lectures in Boston, so the Irishman’s trip to the United States was a noteworthy botanical event.

Like all industrious botanists of the time, Harvey maintained a large network of correspondents who could provide him with information and with specimens. It would be difficult to find an algologist of that period who did not have contact with him. Since he was working at the same time that seaweed collecting was popular, many of these individuals were women, some of whom were as passionate and hardworking as himself. Amelia Griffiths (1768-1858) collected along Britain’s western coast and sent materials to Harvey. She was assisted by her maid Mary Wyatt, who under Griffiths’s guidance produced bound volumes of mounted of Devon algae (1834-1840) to which Harvey referred his readers when he published his unillustrated Manual of British Flora (1841). Margaret Gatty (1809-1873), who wrote nature books for children particularly about the seaside, was serious about algae and her herbarium of 8000 specimens, which includes specimens sent by Harvey, is preserved at St. Andrew’s University in Scotland. Among the most impressive presentations of seaweed was that of Anna Atkins who created Photographs of British Algae (1843-1853), a collection of blue cyanotypes, one of the earliest versions of photographs [see Figure].

At Cambridge University Herbarium, there is a collection of hundreds of watercolors of macroalgae, amazingly beautiful and accurate. They were done by Mary Philadelphia Merrifield (1804-1889), an artist who was originally attracted to seaweed for their beauty, but then went on to study them seriously, publishing several scientific articles. When I visited Cambridge, Christine Bartram, the chief herbarium technician, showed me the paintings and told me about discovering them. Shortly after the collection was moved into a new building, Bartram had an inquiry about Merrifield from someone who had bought a house, found Merrifield letters there, and was curious about her. Bartram recalled that during the move she had seen a shoebox marked “Merrifield,” was able to hunt it down, and found the watercolors. Now they are being preserved more fittingly and being studied.

Before I leave the 19th century, I must mention Ellen Hutchins (1785-1815), who has been called Ireland’s first female botanist. She is at the early end of the seaweed craze and lived near the coast in Cork. Like many at the time, she was encouraged to take up nature study as a healthy hobby by a physician in Dublin where she had been sent to convalesce. Though she was never robust and died young, she wholeheartedly devoted herself to botany under the tutelage of James Mackay, curator at the Botanic Garden of Trinity College, Dublin. He suggested that she study seaweeds when she returned home to Cork, and most of her collections are from the Bantry Bay area. He also put her in touch with the algologist Dawson Turner, with whom she exchanged information and specimens, some of new species. As well as preparing specimens, she produced accurate drawings and watercolors. Hutchinson was known for being able to find and correctly identify rare species. Her specimens are now primarily in the Natural History Museum, London, and most of her drawings are at the Royal Botanic Gardens, Kew.

Though it pains me leave seaweed hunters and the 19th century here, I must in order to move on to other wonders of the algal world, including diatoms, the subject of the next post.

Atkins, A. (1843-1853). Photographs of British Algae: Cyanotype Impressions (Vol. 5 volumes).

Harvey, W. H. (1849). A Manual of British Algae. London: van Voorst.

Wyatt, M. (1834-1840). Algae Danmonienses. Torquay: Cockrem.