By Robert Dunlap
In March 2022, I was lucky enough to find a new population of Turk’s cap lilies (Lilium superbum) containing about 500 stems in two colonies in McCracken County while searching for spring ephemerals. Additional searches yielded five more colonies containing another 1,700 individuals, all within about 75 yards of each other.
Due to my unfamiliarity with this plant and the lack of blooms, it took a little research to verify they were Turk’s cap lilies and not their close relative, Michigan lily (L. michiganense). Dichotomous keys usually differentiate between these plants using flower characteristics i.e., tepal curvature and anther length, which is not very helpful if you don’t have a flower to examine. Several online sources mentioned two vegetative characteristics to check: L. superbum has smooth leaf margins (not finely serrate), and the bulbs are white (not yellow). The plants I found exhibited both of these features so I’m going with the Turks cap lily. This plant was found by Mr. Raymond Athey less than 10 miles from this site in 1978, so there is historical evidence supporting the L. superbum identification, as well.
That being said, some botanists are reluctant to rely on the vegetative characteristics described above and feel that positive identification requires examination of flower structures. After being moved to more suitable sites in the future, my hope is that some of these bulbs will produce flowers allowing their identity to be determined beyond any doubt.
The species name is pronounced “superb – um” as opposed to “super – bum” and refers to the flowers, which can be translated from Latin as proud, superb, excellent, splendid, or magnificent. Mr. Linnaeus did a good job naming this plant back in 1762!
Ecology
Turk’s cap lilies are classified as threatened in Kentucky by the Office of Kentucky Nature Preserves and probably occur in less than a dozen counties. They are scattered across the state from Black Mountain in Harlan County in the east to Carlisle County in the west. Threatened plants are defined by the OKNP as “… likely to become endangered within the foreseeable future throughout all or a significant part of its range in Kentucky.” So, the assumption is that their numbers are declining and will continue to do so in the future.
The BONAP map (Biota of North America Project) to the right displays the counties where Lilium superbum occurs in the U.S. Light green counties have stable populations while those highlighted in yellow have populations that are small and possibly declining.
It is generally more common in upland areas along the Appalachian Mountain chain, which includes Black Mountain. So how did they end up in McCracken County and across the Ohio River in southern Illinois? Some botanists have theorized that many southern plant species migrated north and west following the Cumberland River and the Tennessee River, which join up with the Ohio River near Paducah. Perhaps the lilies travelled from the mountains of North Carolina and Tennessee along these waterways over the last several thousand years or so.
Continue reading Native Spotlight: Turk’s cap lily (Lilium superbum)