Natural History in 17th-Century Britain: Nehemiah Grew

4 Grew plum

Transverse section through plum branch, from The Anatomy of Plants, Biodiversity Heritage Library

When I think of Nehemiah Grew (1641-1712), an image of a cross section through a stem appears in my mind’s eye (see above).  I remember Grew as the creator of magnified images of plant tissue that have a rather inorganic feel to them in their rigid rows of cells.  He was doing microscopic studies at about the same time as Robert Hooke, whose illustrations of plant cells are less regular, and somehow have a more organic feel.  They were both attempting to communicate the new world they were exploring and trying to make sense of it.  In an article to commemorate the tercentenary of Grew’s birth, the plant morphologist Agnes Arber (1941) noted that Grew held a mechanistic view of the universe and saw the microscope as a way to clear up mysteries of life by observing its constituents.  Because of this viewpoint he also developed mathematical descriptions and was concerned with how to communicate the scale of objects seen under the microscope.  This is a reminder that at the time there were no adequate standards of measurement for the microscopic world.  So Grew used comparison to give his reader some idea of the size of what he was seeing, for example, that something was one-fifth the size of the cheese mite or the width of a marsh mallow seed.

Another major contributor to the beginnings of plant anatomy was the Italian Marcello Malpighi who like Grew was a physician, though Grew practiced medicine while Malpighi taught in a medical school and also did a great deal of research on animal anatomy.  In fact, he began studying plants because he found animal tissue so complex and wanted to see if the “simpler” structures of plants could give him clues.  Grew and Malpighi are usually mentioned together because in some ways, their work is similar.  They labored independently without any knowledge of the other’s research until Grew produced a paper for the Royal Society of London (RS) shortly before Malpighi sent a manuscript read at an RS meeting.  After that they followed and cited each other work.

The consensus is that they achieved similar results.  Alan Morton  (1981) claims that Malpighi saw more clearly than Grew in some details, but Grew’s culminating The Anatomy of Plants is the fuller and clearer work, with a more integrated view of plant structure.  Agnes Arber (1942) also wrote a comparison of their contributions and contends that Grew may be better known because he wrote in English, while Malpighi published in Latin.  Arber notes:  “His Latin, though lively, is not very correct, and its interpretation is often by no means easy” (p. 15).  But she considers Malpighi’s illustrations, made from his drawings, as excellent.  Some of Grew’s illustrations are noteworthy because, while Malpighi made attempts at depicting microscopic structures in three dimensions, Grew did it more successfully.

Since this set of posts is on British botanists, I’ll end by noting some of Grew’s most important findings, though in many cases, Malpighi also produced similar results.  Grew described the main anatomical differences between roots and stem.  This required a great deal of work examining a variety of different species.  The same was true of deciphering the vascular network in these structures.  Grew admits that he got the idea for the spiral form of vessels from Malpighi, but he came up with the name “parenchyma” for the material packed around the vessels.  While he depicted a great deal of order in plant tissue as orderly, he did not really conceive of cells as the basic unit of plant structure, though Robert Hooke had already coined the term for the structures he saw in cork cambium.  Grew was able to differentiate between the scattered vascular bundles in monocots and the more ordered structures in dicots; he identified the medullary rays in dicot stems as well.  Grew compared the cell walls to woven fibers and more generally compared a plant’s inner structure to a textile fabric.  Arber (1913) quotes a long passage where he describes plant tissue as fine lace with an intricate and delicate texture.  At one point he writes:  “One who walks with the meanest Stick, holds a Piece of Nature’s Handicraft, which far surpasses the most elaborate Needle-Work in the World” (p. 54).

Grew also went into detail on the structure of flowers.  Though he accepted the idea of sexual reproduction in plants, he wasn’t able to work out the process.  He presented much information on seed structure in a variety of species and carefully observed seed development, coining the term radicle for the embryonic root.  He also did simple experiments on the movement of sap, but his major work was anatomical.  For a century and a half after Grew and Malpighi there was little further development in the field.  It may be that it had to wait for the creation of better microscopes, or for further work in plant physiology.  Or perhaps some of the lack of interest in the field may have been due to those images that so intrigue me.  They presented such a well-developed, finished view of plant structure, that others might have considered the job of working out plant architecture to be complete.  After all, plants were simpler than animals, how much more was there to know?

References

Arber, A. (1913). Nehemiah Grew (1641-1712). In F. W. Oliver (Ed.), Makers of British Botany (pp. 42–64). Cambridge, UK: Cambridge University Press.

Arber, A. (1941). Tercentenary of Nehemiah Grew (1641-1712). Nature, 147(3734), 630–632.

Arber, A. (1942). Nehemiah Grew (1641-1712) and Marcello Malpighi (1628-1694): An essay in comparison. Isis, 34, 7–16.

Morton, A. G. (1981). History of Botanical Science. New York, NY: Academic Press.

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Herbaria and More

4 Platanthera psycodes

Platanthera psycodes collected in 1838, University of Michigan Herbarium

Since the cosponsor of the Digital Data in Biodiversity Research Conference (see last post), along with iDigBio, was the University of Michigan, it’s not surprising that there was a trip to its Research Museums Center south of the main campus. Along with a reception, there were tours of the various zoological, paleontological, archaeological, and botanical collections housed there. Naturally, I went on the herbarium tour offered by three botanists who work with the collection: Christopher Dick the director, Richard Rabeler collection manager, and Anton Reznicek curator. As with many large plant collections, the UM staff can only estimate its size: about 1.8 million specimens. Digitization efforts are making for more accurate estimates, but also unearthing more specimens. The herbarium is actively involved in iDigBio and the national digitization effort with more than 560,000 of its sheets digitized. Since the Research Museums Center is a converted warehouse, the herbarium has room to grow, a valuable resource for the future. The herbarium is strong in Michigan plants, including collections from 1837-1838 for a survey of natural resources made at the time Michigan gained statehood (see figure above). Many of these have habitat information, making them valuable in environmental change studies. There is also a large collection amassed by Harley Harris Bartlett, who led the UM Department of Botany from 1927-1944. He used his considerable wealth to fund explorations in the tropics, and so there are a significant number of specimens from these areas, including many wood specimens from Sumatra that are now being digitized. They are particularly important because of the dramatic changes logging has wrought in Sumatra and also because the labels include the names of the trees recorded in the indigenous language.

On my way home from Michigan, I took a rather roundabout route so I could visit the Cornell University herbarium. I wanted to go there primarily because Cornell was the long-time home campus for the botanist/horticulturalist/agronomist, Liberty Hyde Bailey (1863-1959). Bailey had incredible energy and drive during his entire life and became the first dean of Cornell’s agricultural college (Dorf, 1956). He served on Theodore Roosevelt’s National Commission on Country Life which recommended the formation of the 4-H movement, agricultural extension programs, and rural electrification. Bailey retired from the deanship in 1913 when he reached 60 and spent the next 35 years writing on agricultural and horticultural topics as well as studying the taxonomy of palms on which he published extensively.

As the herbarium’s collections manager Anna Stalter explained, Bailey left his extensive herbarium and book collection to Cornell which explains why a third of the specimens are cultivated plants. This makes it interesting horticulturally and associated materials increase its value. Bailey collected seed and plant catalogues from the late nineteenth century through the first half of the twentieth. The herbarium librarian Peter Fraissinet pulled out a selection that were fascinating historical documents. He also showed me an extensive card catalogue maintained for almost 60 years by Bailey’s daughter and assistant Ethel Zoe Bailey. There was a card for each plant variety, noting the catalogue and years it was offered. Researchers interested in heirloom plants and plant lineages still consult it.   Fraissinet also showed me some rare volumes Bailey had collected, including the oldest book in the library, an Italian translation from 1575 of Nicolas Monardes’s work on Mexican plants that includes the first known image of tobacco (see figure below). I’ve read about this treasure, but it was a thrill to see it as well as a German translation of Pietro Matthioli’s commentaries from 1678.

4a Tobacco from Monardes

Tobacco plant pictured in Monardes’s 16th-century work on Mexican plants. Bailey Hortorium Library, Cornell University

Obviously one day was not enough time to even glance at most Cornell botanical treasures, but I did get to see a few of the massive palm pods Bailey collected and was also introduced to a totally different aspect of botany at the Cornell herbarium, its plant anatomy slide collection. Curator Kevin Nixon and senior research associate Maria Gandolfo are heading the NSF-funded project called CUPAC: Cornell University Plant Anatomy Collection. The goal is to digitize the information on 200,000 slides and to image a significant portion of them, at least one from each set of serial sections, often using more than one power of magnification. They also hope to include slides from other institutions’ collections as a way to preserve and make broadly accessible a valuable research tool for future botanists. There are already many images available on their website, and in the future they hope to link the records to the relevant literature. So this is yet another government-funded digital asset available to all researchers, and also I might add, to artists as well since many of the images are stunning and include not only slides but peels of fossil plant structures.

When I left the herbarium I walked through the Cornell Botanic Gardens where living collections complement the horticultural specimens in the herbarium. It’s wonderful to have the two resources so close to each other. And close by is the plant pathology herbarium, still another treasure, but one I had to leave for the future. As my father always said on road trips: “You have to leave something for next time.” On this trip, I had seen a lot, from living plant collections, to personal collections representing place (see post), to herbaria, and the digital future (see 1, 2). I can’t wait to get on the road again.

Reference

Dorf, P. (1956). Liberty Hyde Bailey: An Informal Biography. Ithaca, NY: Cornell University Press.