The Long Trail of Shortia, by Charles Elliott, appeared originally in Horticulture Magazine, August 2001
(continued from yesterday)…
In the autumn of 1886, Charles Sprague Sargent, founder of the Arnold Arboretum and by then America’s most distinguished dendrologist, journeyed to the corner where Georgia, North and South Carolina come together. This mountain region, about 75 miles southwest of the point where George Hyams found shortia, was well outside the previous search range.
Sargent was trying to discover something of the origins of a magnolia whose roots Michaux had collected here in December of 1788. As it turned out, there had been a confusion of names and Sargent’s magnolia venture came to nothing, but in examining Michaux’s journal for that period he noticed something else.
On the day the explorer arrived in the mountains, hungry and cold and suffering from high fever – he had made note of a “Nouvel Arbuste a.f. denteles rampant sur la Montange” (“New shrub with denticulate [minutely notched] leaves flourishing on the mountain”). He apparently collected samples, but said not more about it.
Michaux’s directions to the point where he had camped were so detailed that Sargent was able to follow them easily, and to trace the excursions the plant hunter had made. At the junction of two “torrents,” the Toxoway and the Horse pasture, in a “little fertile plain,” Sargent discovered shortia.
This was almost certainly the source of the plant Gray had come upon in the herbarium in Paris. Many more were later found in the general area (including Oconee County, SC, whence its common name), although because of dam and road building, aggressive collecting and incursions of civilization in the form of farms and second homes, they have once again become rare in the wild.
Why Michaux called it a shrub remains a mystery – shortia is without question an herbaceous perennial, though no doubt it doesn’t show its best face in December. But why Asa Gray termed it “perhaps the most interesting plant in North America” may possibly be answered. This has little to do with its beauty (modest) or its elusiveness (legendary), but rather with the role shortia played in the greatest scientific drama of the 19th century: the debate over Charles Darwin’s ‘Origin of Species.’
In the years before Darwin published his epochal work, Asa Gray had been one of his primary correspondents, supplying him with information and exploring aspects of plant distribution and other key subjects on which Darwin’s thesis would depend. He was one of the very few people to whom Darwin revealed himself, and a man whose own adventurousness in building large ideas out of an infinity of close observations could match Darwin’s own.
In time, though the two of them were far too strong-minded and individual to align their opinions perfectly, Gray would become Darwin’s principal American supporter and spokesman, at the same time doing much to create a modern scientific establishment in the United States.
In 1858, Gray was examining a group of specimens from Japan brought back by Commodore Perry’s expedition. For a long time – indeed, from the time the first collectors had begun sending samples of Japanese species to Europe and America – botanists had been aware of an odd fact: certain plants could be found in Japan and in the eastern United States but nowhere else.
With this flood of new material, the connection appeared even stronger. Now, suddenly, Gray recognized something familiar: a plant almost identical to his own shortia galacifolia. It had been resoundingly named schizocodon uniflorus by a Russian botanist (the Japanese called it iwa-uchiwa, or “crag fan,” from the shape of its leaves), but it was without question a shortia (and would eventually go by that name too).
But how was one to account for this peculiar identity between two so widely separated flora, marooned on opposite sides of the world? Given the still primitive level of understanding about geological history at the time – Gray’s explanation of the connection was brilliant.
He concluded that during the last ice age, the spread of glaciers had forced plant species common to the entire North Temperate Zone of American and Asia to retreat southwards, and only where there was room for them to shelter in agreeable surroundings (as in Japan and the eastern United States) did they survive.
When the glaciers melted back, changed conditions made it impossible for many species – including shortia – to follow, and they were left isolated. Gray’s thesis fit beautifully into Darwin’s grander argument, and helped support it. Many plants, from pachysandra to magnolias, had been used to illustrate the Japan-America link.
But shortia, still at that date blooming unseen in the Carolina mountains, already represented something special to Asa Gray. It must have fascinated him more than ever, maybe even enough to make him call it “perhaps the most interesting plant in North America.”
Editor’s note: A big thanks goes out to Tammy DeLauter Fletcher, who took the time to point out to me Andre Michaux’s contributions to botany and to Appalachia.