Grouped Flower Seeds: A Microscopic Marvel of Victorian Leisure

“Grouped Flower Seeds” A prepared microscope slide arrangement

Grouped Flower Seeds: A “fine exhibition slide” prepared microscope slide arrangement of 92 angiosperm seeds glued on an opaque background. Produced by: W. Watson & Sons, High St., London, circa 1890. (10X, stack and stitch)

Decoding Seed Arrangements on a Microscope Slide Provides Insight Into Nineteenth-Century Botany

William Watson and Sons, a company based in London (1834-1957), was a major supplier of optical instruments and prepared microscope slides, selling through catalogs in England and the United States between 1834 and 1957. Why would a company produce and market a microscope slide featuring flower seeds arranged in a symmetrical pattern? There are no indications that “Grouped Flower Seeds” (GFS) was intended to serve a purpose in academic biological study. Simply put, the GFS slide was made to be an entertaining novelty for the thriving amateur microscopist market of the time. From 1837 to 1901, a period often referred to as the “Golden Age of Natural History,” nature study was a popular pastime among many biologists. Having a microscope in the home was common among families well-off enough to have leisure time. Exploring nature’s microscopic world was a hobby enjoyed by many microscope owners, while others, less involved, might set up a microscope with slides as a conversation “seed-crystal” during social functions.

Grouped Flower Seeds is a dry mount with an opaque black background requiring oblique or other angled, top-stage illumination for microscopic viewing. Ninety-two tiny seeds are glued into a geometric pattern, surrounded by a metal collar to prevent the coverslip from touching the seed arrangement. Outside the mount, gloss enamel paint seals the chamber from external humidity. No mounting medium fills the space between the seeds and the coverslip, making for a fragile slide if banged or dropped. After 1907, “Ltd.” was added to the Watson label; its absence indicates that the GFS slide was produced prior to that year. Notice the glass slide’s finished edges and corners, as well as the black enamel ring sealing the specimen.

The slide’s creation date is estimated to be between 1890 and 1907. The approximation was inferred by comparing the labels affixed to GFS with matching label designs used by W. Watson & Sons, as illustrated in Bracegirdle’s Compendium of Antique Microscope Slides. Additionally, a W. Watson & Sons advertisement listed a slide titled “Grouped Flower Seeds” in the 1893 edition of Hardwick’s Science Gossip, confirming the existence of a slide with the same name that the company offered during the corresponding time range (Hardwick, 1893). Since W. Watson & Sons resold slides made by other commercial preparers under their label, the actual creator of GFS is not known, but with databases containing digitized catalogs, magazines, newspapers, and books of the period rapidly growing online, the GFS artisan may yet be uncovered.

William Watson started his business as an optician’s shop in London, England, in 1837. By 1876, the company had grown from manufacturing spectacles and magnifying glasses to producing microscopes and cameras of its own design. The W. Watson & Sons Co. catalog advertised a large inventory of microscope slides until World War II (1939). At that time, the company was conscripted to manufacture optical instruments for military use. After the war ended, the company, now owned by the founder’s grandchildren, discontinued the prepared slides from its catalog. A few years later, they retired, permanently closing the company’s doors.

By avocation, William Watson was a horticulturist and maintained a personal greenhouse. He conducted experimental crosses between flower varieties and published several studies in respected journals. The extent of Watson’s involvement in producing the GFS slide is unknown. However, he undoubtedly had access to various plant seeds for the slide’s creation—an important consideration when identifying the seeds used to produce the slide (Bracegirdle, 1998).

A Botanical Mea Culpa

Botanists know well that, when teaching about seeds, not everything referred to as a “seed” is precisely that. To be botanically correct, “seed” should be limited to the reproductive unit containing the embryo of the plant-to-be, along with its stored food and encapsulating seed coat or test. Seeds are often embellished with additional parts derived from the parent plant’s floral remnants that aid the “true seed” in its protection and/or dispersal (Figures 3 & 4). However, even botanically cognizant individuals casually refer to both true seeds and “seeds with accessories” simply as “seeds.” Since practitioners in the sciences need precision when speaking or writing formally, “disseminule” is the botanical term of choice for both true seeds as well as those carrying extra parts. Disseminule is a catchall term encompassing all variations of reproductive packages, botanically referred to by terms such as aril, achene, capsule, caryopsis, nut, drupe, and true seed. Sometimes, an entire plant is considered a disseminule, as in the case of tumbleweeds. “Propagule” and “diaspore” are other terms for botanical procreative packages. “Diaspore” was introduced in 1927 by Sernander as a term restricted to angiosperm reproductive units (Booth, 1988). “Propagule” is a term with the most “wiggle room,” as its definition includes both sexual and asexual methods of reproduction, even extending to a horticulturist’s leaf and stem cuttings. The botanical terminology used in this article is in accordance with that used in the seminal work on seed dispersal by Leendert Pijl, first published in 1969 by Springer-Verlag, with a digitized version currently available from Wiley Online Library at: http://onlinelibrary.wiley.com/doi/10.1002/fedr.19710810814/abstract.

Grouped Flower Seeds Identification Key 1) Silene latifolia alba 2) Oxalis stricta 3) Portulaca pilosa 4) Cinquefoil 5) Senecio vulgaris 6) Carpenula 7) Nemesia sp. 8) Orobanche? 9) Antirrhinum sp. 10) Digitalis purpurea 11) Nasturtium officionalis or Petunia sp. 12) Gentiana

Seed Identification Keys Are the Rarae Aves of Biological Manuals

Identifying unknown seeds is a daunting task. Seed taxonomists employ a complex vocabulary that can quickly dishearten the uninitiated, undermining expectations that an unknown seed’s identity could be easily determined through a simple lookup. One factor increasing the task’s tedium is that most authoritative seed descriptions are scattered throughout botanical publications over a wide time span.

White Campion Silene latifolia (=Silene alba).  White Campion, seed number one in the GFS arrangement, is a dioecious, short-lived, perennial herb native to Eurasia, and now an invasive weed found over most of North America (Figure 6). As with many invasive plants, White Campion quickly colonizes disturbed soils, which occasionally might be a newly dug grave. For this reason, along with its habit of nocturnal blooming, the plant has been dubbed “the grave flower” in England. White Campion’s seeds are held within capsules formed by the ovary wall (figure 7). When mature, the seed-capsule splits open at its apical end (partial dehiscence) with tooth-like cusps curving outward as it dries. The urn-like vessel, now surrounded by ten teeth, two for each of the flower’s carpels, will sprinkle out its reproductive contents only when the stem is vigorously moved about by the wind or a passing animal—a dispersal process called “the saltshaker method,” or anemoballism. White Campion was originally classified as Lychnis alba until the 1960s, but since other members of the Lychnis genus split their seed capsules to form five teeth and White Campion makes ten, it was moved into the toothier genus Silene. Recent genetic bar-coding data strongly suggest that species within the Pink family have been taxonomically “over-split,” and a “re-clumping” may lie in the plant family’s future (Mayol & Rossello, 1999).

Searching Bowker’s Books in Print for currently available seed identification guides yields only one result: Seed Identification Manual (Martin & Barkley, 2000). The guide is a reprint of the 1961 edition published by the Regents of the University of California, which lists Alexander Campbell Martin as the sole author – a name familiar to anyone who collected the Golden Guide paperback nature series popular during the 1950s. The guide is profusely illustrated with black-and-white photographs of 600 species of seeds, but, unfortunately, the reissued version of the book has reproduced the pictures with a lower quality than the original edition. Additionally, unfortunately, the book does not include a key, so identification requires flipping through numerous pages to match the unknown seed with the corresponding images. Thanks to used book dealers listing their stock online, the first edition is findable, albeit requiring patience.

oxalis seeds attached to pod
Oxalis, commonly known as wood sorrel, employs a method of seed dispersal known as ballistic dispersal. When the seeds mature, they are enclosed in a capsule that builds up internal pressure as it dries. Once the pressure becomes too great, the capsule bursts open explosively, flinging the seeds as far as 1-2 meters. This process relies on the shrinking walls of the capsules as they dry, which creates a spring-like effect. When it splits, the capsule twists, dispersing the seeds in different directions. The old capsules are clear and shriveled. A seed that misfired remains stuck on the pod.

Four other out-of-print seed identification guides can usually be obtained with little difficulty. The Illustrated Taxonomy Manual of Weed Seeds (Delorit, 1970) covers 192 species, featuring a dichotomous key to aid in identification, while Weed Seeds of the Great Plains: A Handbook for Identification (Davis, 1993) covers 280 species, utilizing a polychotomous key. Both books contain excellent color photographs. The USDA’s 1963 agricultural handbook, Identification of Crop and Weed Seeds, covers 623 species, accompanied by black-and-white photographs, which are referenced through a “drill-down” series of technical keys. The handbook is agriculturally oriented and, as a result, provides the best coverage of Graminae (grass family) seeds among all the references. Once one begins seeking to identify an unknown seed, the importance of having as many references as possible is quickly realized.

Online Seed Identification Databases

The two most extensive seed identification guides available online are the United States Department of Agriculture’s The Family Guide to Fruits and Seeds (FGFS) (available at http://nt.ars-rin.gov/sbmlweb/OnlineResources/frsdfam/) and Colorado State University’s SeedImages.com (CSU-SI) (available at http://seedimages.com). At the time of this writing, a $30-per-semester subscription is required to access the CSU-SI database.

Both the FGFS (3,216 images) and CSU-SI (1,700 images) websites offer tutorials for utilizing their databases, and both feature search programs that provide a clickable list of “legal” seed descriptors used in each database—a helpful feature in a field fraught with synonyms.

Searching the CSU-SI database will return a list of seed pictures with descriptors that match the searched-for term, as well as all other descriptors linked to that picture. This is a significantly different process from working through a printed dichotomous key, where the researcher cannot proceed if the necessary information to respond to a morphological question set is unknown. Skipping ahead in a taxonomically based dichotomous key obliterates the tool’s purpose and value, even though jumping ahead and working a key in reverse can be instructive. In contrast, computer searches of online seed databases are nonlinear and remain workable with just a few descriptors. When using the CSU-SI database, each seed picture displays the entire list of “legal” descriptors for the seed. Comparing the picture with its associated terms is a vocabulary-building process that enables the researcher to refine their next search attempt (Figure 5).

In the FGFS database, the seed’s descriptors are linked to the taxonomic plant families, so the search returns a list of all the seeds in that plant family in the online database. Sifting through such a large number of pictures to identify a seed is time-consuming, but it is in keeping with the key’s stated objective of being a “Guide to Plant Families.”

The gold standard for seed taxonomists is physically matching the unknown seed with known specimens in a seed herbarium collection. The FGFS was created by photographing examples held by the U.S. National Seed Herbarium (BARC) at the U.S. National Arboretum in Washington, D.C., which, with 120,000 seed taxa, is one of the largest in the world. Researchers can arrange with the BARC to have specimens drawn from the collection for close examination.

 

How to footnote this page: Reiser, Frank W. (2025) Grouped Flower Seeds: A Microscopic Marvel of Victorian Leisure, Available at: https://wp.me/PaLJ0g-1GW

Acknowledgments

I would like to thank Thomas F. Wieboldt, Curator, Massey Herbarium, Dept. of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, for his assistance with several seed identifications and Lisa Maria Martin, Omaha, NE, for her editorial guidance.

References

Bracegirdle, B. (1998). Microscopical Mounts and Mounters. Oxford, England: Seacort Press.

Delorit, R. J. (1970). Illustrated Taxonomy Manual of Weed Seeds. River Falls, WI: Agronomy Publications.

Davis, L.W. (1993). Weed Seeds of the Great Plains: a handbook for identification. Lawrence, KS: University Press of Kansas.

Gleason, H.A. & Cronquist, A. (1991). Manual of the Vascular Plants of Northeastern United States and Adjacent Canada. New York, NY: The New York Botanical Garden.

Martin, A.C. & Barkley, W.D. (2000). Seed identification manual. Copy of 1961 ed. Caldwell, NJ: Blackburn Press.

Musil, A. (1963). Identification of Crop and Weed Seeds: Agriculture Handbook 219. U.S. Department of Agriculture. Washington, D.C.

Oregon State University Anthropology Resources. Definitions of Anthropological Terms. Available at http://oregonstate.edu/instruct/anth370/.

Pijl, I., van der. (1969). Principles of Dispersal in Higher Plants. Springer-Verlag. Dusseldorf. Germany.

W. Watson & Sons. (1893). Advertisement listing prepared microscope slides. Hardwick’s Science Gossip, London, Xii.

__The GFS slide is in the personal collection of the author, and all photographs are by the author.