L. superbum and L. michiganense are very similar perennial forbs. These tall lilies are identified by the backward curving tepals. This completely reveals the stamens and the pollen.
The stems are smooth, round and green, unbranched below the inflorescence. Height can reach 5 to 7 feet with L. superbum tending to be taller.
Leaves form evenly distributed whorls on the stem and are alternate on the upper side branches. Leaves are lanceolate in shape, with smooth edges and parallel veins. They can be 4 to 18x longer than wide, are held horizontally, with the upper whorls upward ascending, and then drooping at the pointed tips. Surfaces are without hair but L. michiganense tends to have somewhat rough lower leaf surfaces along the veins and margins. L. superbum being taller has more whorls (6 to 24) with 3 to 20 leaves per whorl, 3 to 9 being typical; L. michiganense has fewer whorls (4 to 12) with 3 to 13 leaves per whorl, 3 to 7 being typical. Old mature plants will have the most leaves per whorl.
The inflorescence consists of long stalked flowers, appearing as singles on in an umbel of 2 or 3, branching from the top of the stem and the upper leaf axils; 1 to 11 flowers in L. michiganense, buds are rounded in cross-section; 1 to 22 flowers in L. superbum with buds more triangular in cross-section; occasionally both species can produce many more flowers.
The flowers are pendant and not fragrant. The 3 sepals and 3 petals look the same (commonly called 'tepals') and as the flower opens they flare outward and then reflex with the tips frequently touching in L. superbum; these are yellowish orange near the base and then shade to reddish orange. L. superbum tends to have a more yellow-green base to the tepals as the nectaries are exposed giving resemblance to a yellow-green star - less noticeable in L. michiganense. On both species the tepals have darker colored speckles. There are 6 stamens, strongly exserted beyond the tepals with anthers up to 1/2 inch long. Those of L. superbum are more strongly exserted, the filaments parallel for much of their length before spreading widely with anthers that are darker - magenta to purple. Those of L. michiganense diverge and spread sooner with anthers magenta to lighter color. The single style, is pale green with spotted color near the tip in L. superbum and in L. michiganense it is red or reddish mostly near the tip.
Seed: Curiously, when the seed head forms, it will turn upward as it matures. Inside are hundreds of wafer thin disc shaped seeds.
Habitat: These plants are becoming uncommon in the wild due to cultivation and roadside mowing. Like most lilies the plants grow from a bulb with offsetting rhizomes. L. superbum has a white bulb and the rhizomes branch; L. michiganense has a yellow bulb and the rhizomes do not branch. L. superbum prefers sites that are more moist such as moist meadows and thickets, rich wood openings and the edges of marshes and is adapted to somewhat less sun, whereas L. michiganense is more adapted to prairies, ditches, woodland edges where it gets more sun.
Names: The genus Lilium is derived from the Greek word 'lirion' for lily. The species name superbum, means 'superb'; and michiganense means 'of Michigan.' The accepted author of the plant classification for L. superbum - 'L.', refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy; for L. michiganense, ‘Farw.’, refers to Oliver Atkins Farwell (1867-1944) American Botanist, largely self-taught in botany, he taught school for a few years, then became curator and librarian of the herbarium at Parke, Davis and Company, a drug firm, where he was in charge of pharmacognosy of raw botanical product. His papers are Michigan Technological University.
Other comparisons: There are several other lilies that have reflexed petals and sepals of this color range. The one most often confused is the Tiger Lily, Lilium lancifolium. There the most easily distinguishing characteristics are lanceolate shaped leaves that are alternate, not in a whorl and the presence of dark bulbils in the leaf axils on the stem.
Above: The inflorescence can be a single or a group of 2 or 3 long stalked flowers at the top of the stem and from the upper leaf axils. 2nd photo - Defying the normal, these lilies shown in the Upland Garden in the summer of 2000 with former Gardener Cary George, greatly exceeded the average height of the species. Both photos of Turk's-cap Lily. The stamens of L. superbum remain close to the style until spreading at the anthers, which are darker than those of L. michiganense.
Below: Leaf whorls of large mature plants - lower whorls have more leaves. 1st photo - Michigan Lily, 2nd photo - Turk's-cap Lily which has more leaves per whorl.
Below: 1st photo - The tepals of Michigan Lily, L. michiganense, are yellow-orange near their base without the green star-like base of L. superbum (2nd photo) and the stamens spread further and begin spreading nearer the base of the filaments.
Below: Flowers of Turk's-cap Lily.
Below: 1st photo - The upward turned seed heads of late fall. They will remain throughout the winter if the stalk is not blown down. 2nd photo - Each seed pod has several stacked vertical rows of wafer thin seeds.
Below: A stand of Turk's-cap Lily in the Upland Garden.
Below: - The bulb of Michigan Lily with two newer offsets.
Notes: Eloise Butler first noted L. superbum in the Garden in 1908 in which she year she also planted more; she logged planting a dozen bulbs in 1910 that were obtained from Northrup King (Seed and Nursery Company) and she planted it again in 1911, '13, '14 and '17, the latter found within Glenwood Park which partially surrounded the Garden. As it is not native there, she either mis-identified it or it had been planted there. But on Oct. 6, 1917 she planted more from Kelsey's Nursery on the East Coast. L. michiganense is indigenous to the area around the Garden, but was not originally found in the Garden. Curator Martha Crone planted it in the Garden in June 1946 (and also L. superbum). L. michiganense is native to most counties in the eastern half of Minnesota and a few further west in the west-central part of the state. L. superbum is not native to the state but widely introduced. It is native the the SE Quadrant of the U.S. L. michiganense has been replanted as recently as 2012 by Curator Susan Wilkins, who also added L. superbum in 2009.
Only two lily species are native to Minnesota: L. michiganense, Michigan Lily; and L. philadelphicum, Wood Lily.
Eloise Butler wrote the following: "Of our three native lilies the Turk’s-cap, although not the lily of Palestine, may be said to surpass the glory of Solomon, as it is arrayed in recurved orange-red petals flecked with spots of purple. Sometimes as many as forty blossoms are borne on a single plant." Published July 16, 1911, Minneapolis Sunday Tribune.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"