40th Parallel Expedition
U.S. Geological Exploration of the Fortieth Parallel - Clarence King
The journey to the commencement point of an expedition can often be as adventurous as the expedition itself. While sailing from New York to San Francisco to begin the U.S. Geological Exploration of the 40th Parallel, Botanist William Bailey stated, “I saw the most gorgeous vegetation which I have ever yet beheld. The trees were hung down with vines and creepers, and huge palms, bamboos, and an infinite number of other plants were matted together.”
Botanists William Bailey and Sereno Watson collected approximately 19,000 plant specimens at the conclusion of King’s expedition. Although the expedition traveled through California, Nevada, Utah, and Colorado over five exploring seasons to map its topography and discover its resources, plants were only collected in Nevada and Utah from 1867 to 1869.
Asa Gray appointed Bailey as botanist of the expedition. Bailey identified species such as Bailey’s buckweet (Eriogonum baileyi) and the saltbush Obione truncate (now known as Atriplex truncate). He spent nine months collecting plants, but a persistent illness caused him to resign. Sereno Watson, who was previously an unpaid volunteer helping with the topographic studies, replaced Bailey.
Watson observed that the flora of the valleys of the Great Basin was quite distinct, and organized his collections into three groups based on habitat: alkaline species, aquatic and meadow species, and species growing in dry conditions. Watson was the first to describe the Brassicaceae species Arabis longirostris (renamed Streptanthella longirostris), which he found on Stansbury Island of the Great Salt Lake, and was one of 49 alkaline species collected. The goldenrod Solidago elongata is as an aquatic/meadow species. Watson found the plant growing on the stream banks of the canyons, and of the 170 aquatic/meadow species collected, it was one of ten that did not grow past the Rocky Mountains.
Watson also collected the milk-vetch Astragalus iodanthus, which grew—along with 304 other species—in dry locations, exposed to intense heat and drought. Watson noted that, “The source of supply of moisture by which life is sustained… through the droughts of summer has been a matter of doubt.” He conducted field experiments to measure moisture-loss, questioning whether the plants were “in some degree air-plants, drawing the requisite moisture from the atmosphere itself,” or if, “the pubescence or glutinous secretion that often covers [the leaves] prevent... the usual evaporation of the juices.” From the rudimentary experiments, Watson could only conclude that the plants were obtaining their moisture from the soil, even though it appeared to be dry.
Along with the valley flora, Watson listed a total of 393 species from the mountains. Stellaria kingii was found in the East Humboldt Mountains of Nevada and was named after King. Species, such as Caulanthus hastatus, were collected from the Wahsatch and Unita Mountains, and Watson claimed that there was “much more extensive flora here than in the mountains of the Basin, adding 224 species, 47 genera, and six orders to those previously collected.”
Watson also made a collection of mosses and lichens, and even compiled a list of introduced plants. He organized his and Bailey’s extensive botanical findings into volume five of the expedition report, and his detailed observations of plant habitats made it one of the greatest survey reports written.
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Harvard University. “Sereno Watson Papers.” Library of the Gray Herbarium, http://www2.huh.harvard.edu/libraries/archives/WATSON.html
Harvard University. “William Whitman Bailey Papers.” Harvard University Herbaria, http://www2.huh.harvard.edu/Libraries/archives/BAILEYWW.html
Moore, J.G. King of the 40th Parallel. Stanford, Calif: Stanford General Books, 2006.
Watson, S. 1871. List of plants collected in Nevada and Utah, 1867-’69: Numbered as Distributed. Washington D.C.: United States Geological Exploration of the 40th parallel, 1871.
Watson, S. United States Geological Exploration of the Fortieth Parallel. Volume 5 Botany. Washington D.C.: Government Printing Office, 1871.
Watson, S. aided by Eaton, E.C.Botany. Washington D.C.: Government Printing Office, 1871. https://archive.org/details/mobot31753000619566
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