Value of Agriculture

Individuals that recognized the importance and value of agriculture formed groups to share ideas and experiences in the early developing years of the newly independent United States. These organizations were initially formed in the states of New York, Massachusetts, Pennsylvania, and South Carolina in the late 1700s (True Reference True1925). In the city serving as the center for the federal government of the United States after the Revolutionary War (History.com 2009), the Philadelphia Society for Promoting Agriculture formed in 1785 (Anonymous 1808; True Reference True1925). This organization compiled Memoirs, which were experiences and observations made by members as well as information conveyed to members from trusted sources that could be shared in attempts to improve land fertility and productivity, livestock management, forage production, seeding methods, animal and plant disease and insect management, hedge plants, crop processing, farm implements, kitchen design, and other aspects of agrarian life. Society membership was not restricted to residents of Pennsylvania but included individuals from other states as well as several foreign countries (Anonymous 1808).

Botany and Medicine Link

Dr. Benjamin Barton, Professor of Natural History, Materia Medica and Botany at the University of Pennsylvania, was a member of the Philadelphia Society for Promoting Agriculture (Anonymous 1811). As a student at York Academy, Barton’s spare time was spent collecting and sketching plant, insect, and animal specimens (Swensen Reference Swenson, Sterling, Harmond, Cevasco and Hammond1997). He developed an interest in medicine as a student at the College of Philadelphia and studied under the tutelage of Dr. Thomas Shippen (Swensen Reference Swenson, Sterling, Harmond, Cevasco and Hammond1997). He continued the study of medicine abroad at the University of Edinburgh in Scotland. Swensen (Reference Swenson, Sterling, Harmond, Cevasco and Hammond1997) reported that Barton also studied medicine in Germany at the University of Göttingen, although evidence of a medical degree does not exist (Yokota Reference Yokota, Boudreau and Pencak2001). After returning to the United States and practicing medicine, Barton joined the University of Pennsylvania to teach botany. In that position, he published the first botany textbook (Barton Reference Barton1803) in the United States (Swensen Reference Swenson, Sterling, Harmond, Cevasco and Hammond1997). In addition to other biological publications, Barton (Reference Barton1798) also published a series of texts on plants with medicinal properties indigenous to the United States titled Collections for an Essay Towards a Medica Materia of the United States. In the Essay, plants with similar medicinal properties were grouped to create a reference for physicians to know which plants could be used as astringents, tonics, stimulants, errhines, salivation stimulants, emetics, cathartics, diuretics, and anthelmintics. One of Barton’s collaborators was botanist and explorer William Bartram, who not only provided plant material to Barton, but shared ethnobotany of Native Americans he observed and gleaned during his explorations of the New World. One such example was food preparation from Smilax roots, which was originally printed in Bartram’s book of explorations (Figure 1; Bartram Reference Bartram1793), then reprinted in Barton’s Essay (Figure 2; Barton Reference Barton1798).

Figure 1. Page 239 from Bartram’s (Reference Bartram1793) Travels Through North and South Carolina, Georgia, East and West Florida, the Cherokee Country, the Extensive Territories of the Muscogules or Creek Confederacy, and the Country of the Chactaws.

Figure 2. Pages 6 and 7 from Barton’s (Reference Barton1798) Collections for an Essay Towards a Materia Medica of the United States.

One of Benjamin Barton’s students who graduated from the University of Pennsylvania Medical Department was William Darlington. Like his mentor, Darlington was both botanist and physician, but he was also an elected official that represented Pennsylvania in the 14th, 16th, and 17th U.S. Congresses (Anonymous 2023a). Darlington’s first significant botanical publication was a list and description of flowering plants and ferns of Chester County, Pennsylvania, which included notes of medicinal, economic, and artistic uses for plants (Darlington Reference Darlington1837). Ten years later, Darlington (Reference Darlington1847) published Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice or Require the tention, of American Agriculturalists. In the Preface of the text, Darlington stated that one objective of writing the book was to encourage individuals involved in agriculture to better understand and appreciate the science of botany; therefore, he included 23 pages of botanical terms with definitions. He also stated in the Preface that although he appreciated the three economic aspects of botany (agricultural, medicinal, and artistic), his primary overall objective in writing the book was to systematically describe plants of immediate interest to the American agricultural community, especially those located in the middle states (his term; Darlington Reference Darlington1847). He stated that every intelligent agriculturalist should recognize the plants in Agricultural Botany regardless of whether they are encountered in fields, gardens, or woodlands.

Darlington’s First Edition

To achieve his overall objective, Darlington (Reference Darlington1847) followed the method of Linnaeus to describe 485 species of plants, which included about a dozen nonflowering ferns, mushrooms, lichens, seaweed, ergot, mold, rust, and other fungi. For each of the plants, Darlington (Reference Darlington1847) provided both genus and specific epithet as well as English and foreign common names, taxonomic description, habitat, fruiting period, whether introduced or indigenous, and observations made of the plant. Observations written about these weed species were not limited to his personal experiences but included those of others as illustrated in the observations for butter and eggs (Linaria vulgaris Mill.) (Figure 3), information supplied by Mr. Watson. Darlington also included a reference list of the names of 106 botanical authorities of plants in his text. Little information was provided in the text on weed management, except for a few species, aside from encouraging agriculturalists to prevent seed production, increase seeding rates of cultivated crops, and be vigilant to remove weeds. However, Darlington (Reference Darlington1847) shared management thoughts that Canada thistle (Cirsium arvense Scop.), which he called field thistle, could not be controlled by plowing. His conclusion about Canada thistle control was based on weed biology observations conducted and reported to the Society instituted at Bath by William Curtis (Reference Curtis1780), then printed in Volume 2 of Curtis’ Flora Londinensis (Reference Curtis1798) with the scientific name Carduus arvensis.

Figure 3. Entry for butter and eggs (Linaria vulgaris L. (USDA 2023) showing botanical description and observations of this species (Darlington Reference Darlington1847).

Near the end of Agricultural Botany, Darlington (Reference Darlington1847) summarized into lists plants he considered most important. He compiled a list of 57 plants already cultivated for human food production with an additional 27 species suitable, but not cultivated for that purpose. He listed 30 plants, of which only one-third were cultivated, as food for domesticated animals. A third list of 37 plants Dr. Darlington thought could be grown to produce condiments or beverage, whereas the fourth list of 35 plants contained medicinal properties but fewer than one-half were cultivated. Ninety-one plants he considered useful for domestic or rural commercial art.

The last two lists compiled by Dr. Darlington are of particular interest to weed scientists. Figure 4 is his list of the most troublesome weeds in U.S. agriculture at that time. In this list, Darlington (Reference Darlington1847) wrote genus and specific epithets of the 73 plants he considered the most “pernicious and troublesome” weeds, assuming that these plants should be eradicated from U.S. agriculture. Webster (Reference Webster1828) defined pernicious as “destructive” with “the quality of killing, destroying, or injuring.” Table 1 lists these plants along with Darlington’s proposed common name, popular common name as well as current scientific name and common name. Among the 73 pernicious and troublesome weeds, Darlington considered 15 the worst of the worst. These 15 plants, which he described as “eminently pernicious” are shown in Table 2, also with Darlington’s proposed and popular common names and current scientific and common names. Figure 5 and Table 3 show Dr. Darlington’s list of plants he described as “mere” weeds on farms. Although he listed only 39 weeds specifically by scientific name, among several genera described by Torrey and Gray (Reference Torrey and Gray1838), Darlington (Reference Darlington1847) opined that all species should be considered weeds: Aster, Carex, Cirsium, Cyperus, Equisetum, Erigeron, Eupatorium, Euphorbia, Juncus, Lobelia, Oenothera, Panicum, Polygonum, Pteris (and all ferns), Rubus (all wild species), Scirpus, Solidago, and Sphagnum (and all other mosses) should be viewed as weeds when emerged in agricultural habitats. Thus, he considered the total list “about” 120 species of plants.

Figure 4. Image of Darlington’s (Reference Darlington1847) List VI Pernicious and troublesome plants from Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice, or Require the Attention, of American Agriculturalists.

Table 1. Darlington’s (Reference Darlington1847) list of “pernicious and troublesome” weeds from Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice, or Require the Attention, of American Agriculturalists with proposed and popular common names of the period and current nomenclature and common names. Blank cells indicate no name provided.

^a Unless otherwise stated.

^b Only R. toxicodendron stated in Darlington’s (Reference Darlington1847) list of pernicious weeds; however, in the text it is combined with R. radicans as Torrey and Gray (Reference Torrey and Gray1838) list as a single species of climbing and not climbing in The Flora of North America.

Table 2. Eminently pernicious weeds from Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice, or Require the Attention, of American Agriculturalists (Darlington Reference Darlington1847) with proposed and popular common names of the period and current nomenclature and common names. Blank cells indicate no name provided.

^a Unless otherwise stated.

Figure 5. Image of Darlington’s (Reference Darlington1847) List VII Plants that are chiefly mere Weeds, from Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice, or Require the Attention, of American Agriculturalists.

Table 3. Darlington’s (Reference Darlington1847) list of “mere” weeds from Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice, or Require the Attention, of American Agriculturalists with proposed and popular common names of the period and current nomenclature and common names. Blank cells indicate no name provided.

^a Unless otherwise stated.

^b Synonym of Taraxacum officinale F.H. Wigg. ssp. officinale on USDA NRCS 2023.

^c Synonym of Lyonia mariana (L.) D. Don on USDA NRCS 2023.

The Second Edition

A second edition of Darlington’s book was published in 1859. However, due to Darlington’s failing health, updates to the text were done by George Thurber (Darlington and Thurber Reference Darlington, Thurber and Thurber1859), Lecturer of botany and materia medica at New York College of Pharmacy and later Chair of botany and horticulture at Michigan College of Agriculture (Anonymous 2023b). Thurber listed and described, in the same manner as the first edition, 164 additional plant species. Artists were used to sketch 140 images of plants or plant parts that were carved into wooden blocks for printing to aid botanical understanding and plant identification (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). Drawings used to illustrate this edition included 140 images, among which one was of an enlarged grass floret; 65 were plants useful for lumber, live hedges, ornamental, medicinal, food, or other benefits to humanity; and the remaining 74 images were plants considered weeds. An example is shown in Figure 6 of giant ragweed, called great ragweed in the text (Ambrosia trifida L.). This 2nd edition is likely the first weed identification guide with images printed in the United States. Perhaps because of the significance of revisions made to the second edition, the title of the book was changed to American Weeds and Useful Plants: Being a Second and Illustrated Edition of Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice or Require the Attention, of American Agriculturalists (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). Multiple publishers printed the revised edition, as the senior author has seen at least three different publishers listed on title pages of American Weeds.

Figure 6. Drawn image of giant ragweed (Ambrosia trifida L.), which the authors called great ragweed, from American Weeds and Useful Plants: Being a Second and Illustrated Edition of Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice, or Require the Attention, of American Agriculturalists (Darlington and Thurber Reference Darlington, Thurber and Thurber1859).

American Weeds does not contain the lists of weeds nor plant uses published in Darlington’s first edition. However, four pages of text titled “Weeds” that provide an overview of weed management suggestions were included in the second edition. Whether this section was written by William Darlington or George Thurber is not stated. Many of these concepts are basic weed management principles, but this book may be the first to put these in print. In this section titled “Weeds” is provided the best definition for a weed is “the old one”, “a plant out of place” (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). The authors also stated that the weeds most problematic in American agriculture were those that either migrated from the Old World or warmer parts of the United States (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). The authors introduce the text by asserting that farmers primarily want two questions about weeds answered: how weeds get on the farm and how to get them off the farm (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). To help address these questions, the authors offered several recommendations. For the first weed management recommendation, these physicians drew a parallel to a healthy human body fighting disease: weeds cannot be avoided by good farming methods, but good farmers remove weeds when they appear on the farm. The authors present the concept that soil not occupied with desirable plants provides open space for weeds to emerge; therefore, make every effort to maximize areas occupied with desirable plants and use production practices that enable desirable plants to compete with weeds (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). The authors declare that some weeds emerge because crop seed or manure is contaminated with weed seed, whereas other weeds produce seed equipped with natural dispersal mechanisms that facilitate movement by wind or animals (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). They affirm that weed seeds remain viable when buried in soil at depths unfavorable for germination; therefore, weeds should be controlled before seeds form (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). The concept published by Jethro Tull (Reference Tull1733) more than a century before Thurber revised Darlington’s book, that weeds that spread vegetatively by roots and underground stems are more difficult to control than annual weeds, is stated for agriculturalists in the United States. The authors suggested that the best strategy to conquer perennial weeds is to control them before they develop underground stems capable of producing new shoots (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). In addition, they suggested that every piece of perennial root or stem fragmented by tillage be removed from fields to reduce weed spreading caused by scattering plant parts. They went on to suggest that the only effective method to control perennial weeds is to completely exhaust reserves stored in vegetative fragments (Darlington and Thurber Reference Darlington, Thurber and Thurber1859). The final suggestions offered by the authors for weed management is preventing plants from breathing by keeping the leaves removed and preventing flowering, thereby eliminating seed production (Darlington and Thurber Reference Darlington, Thurber and Thurber1859).

Weeds of American Agriculture

A posthumous article by Dr. William Darlington (Reference Darlington and Newton1866) on the most common and troublesome weeds in American agriculture was published in Report of the Commissioner of Agriculture for the Year 1865. This article, titled “Weeds of American Agriculture,” asserted that the goal was for every young, aspiring, and intelligent farmer to recognize these 100 weeds and know their weedy characteristics (Darlington Reference Darlington and Newton1866). Whereas most of the weeds and weedy characteristics listed in this article had appeared in the two earlier publications, a few new weeds were listed: wild radish (Raphanus raphanistrum L.), oneseed bur cucumber (Sicyos angulatos L.; possible typographical error in Report, should be Sicyos angulatus L.), bishop’s goutweed (Ǽgopodium podagravia L.; potential typographical error in Report, should be Aegopodium podagraria L.), European stickweed [Echinospermum lappula Lehm. = Lappula squarrosa (Retz.) Dumort.], and Canadian waterweed [Anacharsis canadensis Planchon, Udora, Nutt) = Elodea canadensis Michx.] (WFO 2023a).

Selective weed management options were limited at the time all three of these documents were originally published. In addition to a list of 100 weeds in the article Weeds of American Agriculture (Darlington Reference Darlington and Newton1866), general weed management suggestions were made as well as specific control suggestions for a few weeds, such as the importance to prevent seed production for weeds such as blindeyes (Papaver dubium L.), which had the common name field poppy in the article, common mullein (Verbascum thapsus L.), wild carrot (Daucus carota L.), and spiny cocklebur (Xanthium spinosum L.), which had the common name thorny clot-bur. Various forms of mechanical control were suggested for some weeds: close grazing by sheep in the spring to control St. Anthony’s turnip Ranunculus bulbosus L.); annual plowing to control false flax [Camelina sativa (L.) Crantz]; production of crops conducive to cultivation, such as hand hoeing, to control Canadian horseweed [Erigeron canadense (L.) = Conyza canadensis (L.) Cronquist.] (WFO 2023b), oxeye daisy (Leucanthemum vulgare Lam.), and Canada thistle. Severing the perennial rhizome with a chisel-shaped spud below the soil surface was recommended to control common corncockle (Darlington called cockle or rose campion) (Agrostemma githago L.), Canada thistle, common thistle [Cirsium lanceolatum (Savi) Ten.], and New York ironweed [Vernonia noveboracensis (L.) Michx.], which Dr. Darlington called wild iron weed. Addition of lime to soil was suggested to control bitter dock (Rumex obtusifolius L.), which was called broad-leaved dock. A drastic control recommendation compared to hoeing or cultivation was given for arrowleaf tearthumb (Polygonum sagittatum L.): ditching to drain the site, meaning change the soil hydrology where populations existed, perhaps the most laborious recommendation of all that were made (Darlington Reference Darlington and Newton1866). Control of upright sedge (Carex stricta Lam.), called tussock sedge in the article, included digging plants, incinerating dried plants, then applying the ash for fertilizer. Darlington’s (Reference Darlington and Newton1866) recommendation for purple nutsedge (Cyperus rotundus L. = Cyperus hydra Mx), called coco in the article, was referenced to and quoted directly from Elliott’s (Reference Elliott1821), A Sketch of the Botany of South Carolina and Georgia: “to plough or hoe the spots in which it grows every day through the whole season.” Fortunately, other management options now exist.

Electronic copies (pdf) of all three of these documents and others can be downloaded from the Weed Science Society of America website at Antique literature | Weed Science Society of America (wssa.net). Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice or Require the Attention, of American Agriculturalists (Darlington, Reference Darlington1847) is at https://wssa.net/wp-content/uploads/antique/Darlington_1847_Useful%20plants%20and%20weeds.pdf; American Weeds and Useful Plants: Being a Second and Illustrated Edition of Agricultural Botany: An Enumeration and Description of Useful Plants and Weeds, Which Merit the Notice or Require the Attention, of American Agriculturalists (Darlington and Thurber Reference Darlington, Thurber and Thurber1859) is at https://wssa.net/wp-content/uploads/antique/americanweedsandusefulplants1859.pdf; Weeds of American Agriculture (Darlington Reference Darlington and Newton1866) pages 509-519 in Report of the Commissioner of Agriculture for the Year 1865 is at https://wssa.net/wp-content/uploads/antique/Report_of_the_Commission_of_Agriculture_for_the_Year_1865.pdf.