Over the last five or six years I have been somewhat obsessed by the origin of the namesake of our local geographic features known as Leatherwood Creek, Lake Leatherwood and the city park of the same name. My curiosity was first sparked by a 1987 Master’s Thesis “A Survey of the Vascular Plants of Carroll County, Arkansas” which noted that eastern leatherwood (Dirca palustris) was known only from historical plant collections for the county, as Murphy was unable to find it here. I found it curious that a plant that sparked a number of local geographical names was not to be found.
The genus Dirca is a very small plant group, with only three species, until a fourth species was discovered in 2007, then named in a 2009 publication by Aaron Floden and colleagues at Kansas State University. The widespread, North America species, eastern leatherwood (Dirca palustris) is found in rich, moist woods.
Western leatherwood (Dirca occidentalis) only occurs in a narrow range near the San Francisco Bay area. The rare Mexican leatherwood (Dirca mexicana) is known from only one population in the mountains of northeastern Tamaulipas, Mexico. And now we have the new species – Ozark leatherwood (Dirca decipiens).
In a 2007, Aaron Floden first saw a leatherwood population in Johnson County, Kansas, and noticed unusual features. Further fieldwork over the next two years found the same plant in two counties in Missouri and two counties in Arkansas – Benton and Carroll. In 2009 Floden and colleagues recognized that this was actually a new, undescribed species, Dirca decipiens.
In May of 2014 I found leatherwood growing at Lake Leatherwood City Park, and simply assumed it was eastern leatherwood. The newly described Ozark leatherwood usually occurs in dry limestone habitats, whereas eastern leatherwood grows near creek bottoms, where I found it. Just last week, I got an email from Brent Baker, a botanist with the Arkansas Natural Heritage Commission, who had recently done fieldwork in the area and believes that most of the leatherwood at Lake Leatherwood City Park is actually the new species Ozark leatherwood (Dirca decipiens).
This is an exceedingly slow-growing shrub with flexible branches. A trunk only two inches in diameter can be a century old. Since the plant has no real material value, it has pretty much been left alone by humans. Finding leatherwood at Leatherwood was special, but for the inner botanical nerd, finding out it is Ozark Leatherwood is downright exciting!